TY  - JOUR
AU  - Ferjančić, Zorana
AU  - Matović, Radomir
AU  - Bihelović, Filip
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1557
AB  - Intermolecular Nozaki-Hiyama-Kishi coupling between alkenylchromium(III) reagents, derived from either (E)-(2-bromoethenyl)benzene or (E)-1-iodo-1-pentadecene, and the conformationally rigid Garner's aldehyde resulted in the stereoselective formation of Felkin-type allylic alcohols in good yields, thus providing an easy access to sphingosines. In addition, when the protecting group in the Garner's aldehyde was changed (from Boc to N-octanoyl), a reversal of stereoselectivity was observed in the reaction with (E)-1-pentadecenylchromium(III), probably as the result of hydrophobic interactions between the long carbon chains of the reaction partners.
PB  - Serbian Chemical Soc, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Diastereoselective addition of alkenylchromium(III) reagents to Garner's aldehyde. The Nozaki-Hiyama-Kishi coupling approach to sphingosines and ceramides
VL  - 79
IS  - 6
SP  - 627
EP  - 636
DO  - 10.2298/JSC130611067F
ER  - 

@article{
author = "Ferjančić, Zorana and Matović, Radomir and Bihelović, Filip",
year = "2014",
abstract = "Intermolecular Nozaki-Hiyama-Kishi coupling between alkenylchromium(III) reagents, derived from either (E)-(2-bromoethenyl)benzene or (E)-1-iodo-1-pentadecene, and the conformationally rigid Garner's aldehyde resulted in the stereoselective formation of Felkin-type allylic alcohols in good yields, thus providing an easy access to sphingosines. In addition, when the protecting group in the Garner's aldehyde was changed (from Boc to N-octanoyl), a reversal of stereoselectivity was observed in the reaction with (E)-1-pentadecenylchromium(III), probably as the result of hydrophobic interactions between the long carbon chains of the reaction partners.",
publisher = "Serbian Chemical Soc, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Diastereoselective addition of alkenylchromium(III) reagents to Garner's aldehyde. The Nozaki-Hiyama-Kishi coupling approach to sphingosines and ceramides",
volume = "79",
number = "6",
pages = "627-636",
doi = "10.2298/JSC130611067F"
}

Ferjančić, Z., Matović, R.,& Bihelović, F.. (2014). Diastereoselective addition of alkenylchromium(III) reagents to Garner's aldehyde. The Nozaki-Hiyama-Kishi coupling approach to sphingosines and ceramides. in Journal of the Serbian Chemical Society
Serbian Chemical Soc, Belgrade., 79(6), 627-636.
https://doi.org/10.2298/JSC130611067F

Ferjančić Z, Matović R, Bihelović F. Diastereoselective addition of alkenylchromium(III) reagents to Garner's aldehyde. The Nozaki-Hiyama-Kishi coupling approach to sphingosines and ceramides. in Journal of the Serbian Chemical Society. 2014;79(6):627-636.
doi:10.2298/JSC130611067F .

Ferjančić, Zorana, Matović, Radomir, Bihelović, Filip, "Diastereoselective addition of alkenylchromium(III) reagents to Garner's aldehyde. The Nozaki-Hiyama-Kishi coupling approach to sphingosines and ceramides" in Journal of the Serbian Chemical Society, 79, no. 6 (2014):627-636,
https://doi.org/10.2298/JSC130611067F . .

TY  - JOUR
AU  - Marjanovic, Jasna
AU  - Divjakovic, Vladimir
AU  - Matović, Radomir
AU  - Ferjančić, Zorana
AU  - Saičić, Radomir N.
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1215
AB  - The stereodivergent synthesis of two hyacinthacine analogues, which relies on an organocatalyzed aldol addition, is described. The aldol addition of dioxanone to an -N-carbobenzyloxy-substituted chiral aldehyde, promoted by both (R)- and (S)-proline, proceeds in reasonable yields with acceptable diastereomeric ratios. The success of the reaction may be due to the use of an acyclic aldehyde acceptor, which allows reagent control of the stereochemical outcome of the key aldolization step in both the matched and mismatched cases.
PB  - Wiley-V C H Verlag Gmbh, Weinheim
T2  - European Journal of Organic Chemistry
T1  - Double Asymmetric Induction in Organocatalyzed Aldol Reactions: Total Synthesis of (+)-2-epi-Hyacinthacine A(2) and (-)-3-epi-Hyacinthacine A(1)
VL  - 2013
IS  - 25
SP  - 5555
EP  - 5560
DO  - 10.1002/ejoc.201300716
ER  - 

@article{
author = "Marjanovic, Jasna and Divjakovic, Vladimir and Matović, Radomir and Ferjančić, Zorana and Saičić, Radomir N.",
year = "2013",
abstract = "The stereodivergent synthesis of two hyacinthacine analogues, which relies on an organocatalyzed aldol addition, is described. The aldol addition of dioxanone to an -N-carbobenzyloxy-substituted chiral aldehyde, promoted by both (R)- and (S)-proline, proceeds in reasonable yields with acceptable diastereomeric ratios. The success of the reaction may be due to the use of an acyclic aldehyde acceptor, which allows reagent control of the stereochemical outcome of the key aldolization step in both the matched and mismatched cases.",
publisher = "Wiley-V C H Verlag Gmbh, Weinheim",
journal = "European Journal of Organic Chemistry",
title = "Double Asymmetric Induction in Organocatalyzed Aldol Reactions: Total Synthesis of (+)-2-epi-Hyacinthacine A(2) and (-)-3-epi-Hyacinthacine A(1)",
volume = "2013",
number = "25",
pages = "5555-5560",
doi = "10.1002/ejoc.201300716"
}

Marjanovic, J., Divjakovic, V., Matović, R., Ferjančić, Z.,& Saičić, R. N.. (2013). Double Asymmetric Induction in Organocatalyzed Aldol Reactions: Total Synthesis of (+)-2-epi-Hyacinthacine A(2) and (-)-3-epi-Hyacinthacine A(1). in European Journal of Organic Chemistry
Wiley-V C H Verlag Gmbh, Weinheim., 2013(25), 5555-5560.
https://doi.org/10.1002/ejoc.201300716

Marjanovic J, Divjakovic V, Matović R, Ferjančić Z, Saičić RN. Double Asymmetric Induction in Organocatalyzed Aldol Reactions: Total Synthesis of (+)-2-epi-Hyacinthacine A(2) and (-)-3-epi-Hyacinthacine A(1). in European Journal of Organic Chemistry. 2013;2013(25):5555-5560.
doi:10.1002/ejoc.201300716 .

Marjanovic, Jasna, Divjakovic, Vladimir, Matović, Radomir, Ferjančić, Zorana, Saičić, Radomir N., "Double Asymmetric Induction in Organocatalyzed Aldol Reactions: Total Synthesis of (+)-2-epi-Hyacinthacine A(2) and (-)-3-epi-Hyacinthacine A(1)" in European Journal of Organic Chemistry, 2013, no. 25 (2013):5555-5560,
https://doi.org/10.1002/ejoc.201300716 . .

TY  - JOUR
AU  - Trmcic, Milena V.
AU  - Matović, Radomir
AU  - Tovilović, Gordana
AU  - Ristic, Biljana Z.
AU  - Trajković, Vladimir
AU  - Ferjančić, Zorana
AU  - Saičić, Radomir N.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/981
AB  - The design, synthesis and biological evaluation of a novel C, D-spirolactone analogue of paclitaxel is described. This is the first paclitaxel analogue without an oxetane D-ring that shows a significant cytotoxic effect (activity one order of magnitude lower than paclitaxel). More importantly, its cytotoxicity is a result of a different mechanism of action, involving mTOR inhibition-dependent autophagy instead of G(2)/M cell cycle arrest-dependent apoptosis.
PB  - Royal Soc Chemistry, Cambridge
T2  - Organic & Biomolecular Chemistry
T1  - A novel C,D-spirolactone analogue of paclitaxel: autophagy instead of apoptosis as a previously unknown mechanism of cytotoxic action for taxoids
VL  - 10
IS  - 25
SP  - 4933
EP  - 4942
DO  - 10.1039/c2ob25514f
ER  - 

@article{
author = "Trmcic, Milena V. and Matović, Radomir and Tovilović, Gordana and Ristic, Biljana Z. and Trajković, Vladimir and Ferjančić, Zorana and Saičić, Radomir N.",
year = "2012",
abstract = "The design, synthesis and biological evaluation of a novel C, D-spirolactone analogue of paclitaxel is described. This is the first paclitaxel analogue without an oxetane D-ring that shows a significant cytotoxic effect (activity one order of magnitude lower than paclitaxel). More importantly, its cytotoxicity is a result of a different mechanism of action, involving mTOR inhibition-dependent autophagy instead of G(2)/M cell cycle arrest-dependent apoptosis.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Organic & Biomolecular Chemistry",
title = "A novel C,D-spirolactone analogue of paclitaxel: autophagy instead of apoptosis as a previously unknown mechanism of cytotoxic action for taxoids",
volume = "10",
number = "25",
pages = "4933-4942",
doi = "10.1039/c2ob25514f"
}

Trmcic, M. V., Matović, R., Tovilović, G., Ristic, B. Z., Trajković, V., Ferjančić, Z.,& Saičić, R. N.. (2012). A novel C,D-spirolactone analogue of paclitaxel: autophagy instead of apoptosis as a previously unknown mechanism of cytotoxic action for taxoids. in Organic & Biomolecular Chemistry
Royal Soc Chemistry, Cambridge., 10(25), 4933-4942.
https://doi.org/10.1039/c2ob25514f

Trmcic MV, Matović R, Tovilović G, Ristic BZ, Trajković V, Ferjančić Z, Saičić RN. A novel C,D-spirolactone analogue of paclitaxel: autophagy instead of apoptosis as a previously unknown mechanism of cytotoxic action for taxoids. in Organic & Biomolecular Chemistry. 2012;10(25):4933-4942.
doi:10.1039/c2ob25514f .

Trmcic, Milena V., Matović, Radomir, Tovilović, Gordana, Ristic, Biljana Z., Trajković, Vladimir, Ferjančić, Zorana, Saičić, Radomir N., "A novel C,D-spirolactone analogue of paclitaxel: autophagy instead of apoptosis as a previously unknown mechanism of cytotoxic action for taxoids" in Organic & Biomolecular Chemistry, 10, no. 25 (2012):4933-4942,
https://doi.org/10.1039/c2ob25514f . .

TY  - JOUR
AU  - Ferjančić, Zorana
AU  - Matović, Radomir
AU  - Saičić, Radomir N.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1056
AB  - A synthetic sequence has been developed for the preparation of 9,10- di-O-diacetyl-4-desmethylene-4β-(3-butenyl)-4α-hydroxy-5-O-mesyltaxicin I- -1,2-carbonate 3, an intermediate in an attempted synthesis of a cyclobutane paclitaxel analogue. A series of reactions of 3 were investigated, including the protection of the sterically hindered C-4α-hydroxy group and the oxidative cleavage of the terminal double bond. Cyclization of 13 to the cyclobutane-containing intermediate failed due to the unexpected instability of the dimethylsilane protecting group under basic conditions.
AB  - Razvijena je sintetička sekvenca za dobijanje 9,10-di-O-acetil-4-desmetilen-4β-(3-butenil)-4α-hidroksi-5-O-meziltaksicin I-1,2-karbonata (3), intermedijera u pokušanoj sintezi ciklobutanskog analoga paklitaksela. Ispitivana je mogućnost dalje hemijske transformacije jedinjenja 3, kao što je zaštita sterno izrazito zaštićene C-4α hidroksilne grupe i oksidativna fragmentacija terminalne dvostruke veze. Ciklizacija jedinjenja 13 nije dala željeni rezultat - intermedijer sa ciklobutanovim prstenom, što je posledica neočekivane nestabilnosti DMS-zaštitne grupe u baznim reakcionim uslovima.
PB  - Serbian Chemical Soc, Belgrade
T2  - Journal of the Serbian Chemical Society
T1  - Synthetic studies towards D-modified paclitaxel analogues
T1  - Sintetičke studije analoga paklitaksela sa modifikovanim D-prstenom
VL  - 77
IS  - 11
SP  - 1529
EP  - 1539
DO  - 10.2298/JSC120626094F
ER  - 

@article{
author = "Ferjančić, Zorana and Matović, Radomir and Saičić, Radomir N.",
year = "2012",
abstract = "A synthetic sequence has been developed for the preparation of 9,10- di-O-diacetyl-4-desmethylene-4β-(3-butenyl)-4α-hydroxy-5-O-mesyltaxicin I- -1,2-carbonate 3, an intermediate in an attempted synthesis of a cyclobutane paclitaxel analogue. A series of reactions of 3 were investigated, including the protection of the sterically hindered C-4α-hydroxy group and the oxidative cleavage of the terminal double bond. Cyclization of 13 to the cyclobutane-containing intermediate failed due to the unexpected instability of the dimethylsilane protecting group under basic conditions., Razvijena je sintetička sekvenca za dobijanje 9,10-di-O-acetil-4-desmetilen-4β-(3-butenil)-4α-hidroksi-5-O-meziltaksicin I-1,2-karbonata (3), intermedijera u pokušanoj sintezi ciklobutanskog analoga paklitaksela. Ispitivana je mogućnost dalje hemijske transformacije jedinjenja 3, kao što je zaštita sterno izrazito zaštićene C-4α hidroksilne grupe i oksidativna fragmentacija terminalne dvostruke veze. Ciklizacija jedinjenja 13 nije dala željeni rezultat - intermedijer sa ciklobutanovim prstenom, što je posledica neočekivane nestabilnosti DMS-zaštitne grupe u baznim reakcionim uslovima.",
publisher = "Serbian Chemical Soc, Belgrade",
journal = "Journal of the Serbian Chemical Society",
title = "Synthetic studies towards D-modified paclitaxel analogues, Sintetičke studije analoga paklitaksela sa modifikovanim D-prstenom",
volume = "77",
number = "11",
pages = "1529-1539",
doi = "10.2298/JSC120626094F"
}

Ferjančić, Z., Matović, R.,& Saičić, R. N.. (2012). Synthetic studies towards D-modified paclitaxel analogues. in Journal of the Serbian Chemical Society
Serbian Chemical Soc, Belgrade., 77(11), 1529-1539.
https://doi.org/10.2298/JSC120626094F

Ferjančić Z, Matović R, Saičić RN. Synthetic studies towards D-modified paclitaxel analogues. in Journal of the Serbian Chemical Society. 2012;77(11):1529-1539.
doi:10.2298/JSC120626094F .

Ferjančić, Zorana, Matović, Radomir, Saičić, Radomir N., "Synthetic studies towards D-modified paclitaxel analogues" in Journal of the Serbian Chemical Society, 77, no. 11 (2012):1529-1539,
https://doi.org/10.2298/JSC120626094F . .

TY  - JOUR
AU  - Ferjančić, Zorana
AU  - Matović, Radomir
AU  - Čeković, Živorad
AU  - Jiang, Yi
AU  - Snyder, James P.
AU  - Trajković, Vladimir
AU  - Saičić, Radomir N.
PY  - 2006
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2772
AB  - A C,D-seco-paclitaxel derivative 26 was prepared from taxine and tested for biological activity. Chemical reactivity of the seco-compounds proved to be substantially modified, with respects to taxoids. The corresponding C,D-seco-taxoid does not show tubulin stabilizing activity or cytotoxicity. Explanation of these observations based on molecular modeling is provided. (c) 2006 Elsevier Ltd. All rights reserved.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Tetrahedron
T1  - Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid
VL  - 62
IS  - 36
SP  - 8503
EP  - 8514
DO  - 10.1016/j.tet.2006.06.080
ER  - 

@article{
author = "Ferjančić, Zorana and Matović, Radomir and Čeković, Živorad and Jiang, Yi and Snyder, James P. and Trajković, Vladimir and Saičić, Radomir N.",
year = "2006",
abstract = "A C,D-seco-paclitaxel derivative 26 was prepared from taxine and tested for biological activity. Chemical reactivity of the seco-compounds proved to be substantially modified, with respects to taxoids. The corresponding C,D-seco-taxoid does not show tubulin stabilizing activity or cytotoxicity. Explanation of these observations based on molecular modeling is provided. (c) 2006 Elsevier Ltd. All rights reserved.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Tetrahedron",
title = "Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid",
volume = "62",
number = "36",
pages = "8503-8514",
doi = "10.1016/j.tet.2006.06.080"
}

Ferjančić, Z., Matović, R., Čeković, Ž., Jiang, Y., Snyder, J. P., Trajković, V.,& Saičić, R. N.. (2006). Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid. in Tetrahedron
Oxford : Pergamon-Elsevier Science Ltd., 62(36), 8503-8514.
https://doi.org/10.1016/j.tet.2006.06.080

Ferjančić Z, Matović R, Čeković Ž, Jiang Y, Snyder JP, Trajković V, Saičić RN. Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid. in Tetrahedron. 2006;62(36):8503-8514.
doi:10.1016/j.tet.2006.06.080 .

Ferjančić, Zorana, Matović, Radomir, Čeković, Živorad, Jiang, Yi, Snyder, James P., Trajković, Vladimir, Saičić, Radomir N., "Synthesis, biology, and modeling of a C-4 carbonyl C,D-seco-taxoid" in Tetrahedron, 62, no. 36 (2006):8503-8514,
https://doi.org/10.1016/j.tet.2006.06.080 . .

TY  - JOUR
AU  - Ferjančić, Zorana
AU  - Matović, Radomir
AU  - Čeković, Živorad
AU  - Saičić, Radomir N.
PY  - 2006
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/259
AB  - The reaction of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I (2) with BF3·Et2O/Bu4NBr can give rise to 4 different products. Each of these products can be obtained selectively, under the appropriate reaction conditions.
AB  - U reakciji α-4(20)-epoksi-5-O-meziltriacetiltaksicina I (2) sa bortrifluorid eteratom i tetrabutilamonijum-bromidom mogu nastati 4 različita proizvoda, u zavisnosti od reakcionih uslova. Svaki od ova 4 proizvoda se može dobiti selektivno, pod odgovarajućim reakcionim uslovima.
PB  - Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Reactions of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I induced by Bf3·Et2O/Bu4NBr
T1  - Reakcije α-4(20)-epoksi-5-O-meziltriacetiltaksicina I sa tetrabutilamonijum-bromidom u prisustvu bortrifluorid-eterata
VL  - 71
IS  - 7
SP  - 705
EP  - 711
DO  - 10.2298/JSC0607705F
ER  - 

@article{
author = "Ferjančić, Zorana and Matović, Radomir and Čeković, Živorad and Saičić, Radomir N.",
year = "2006",
abstract = "The reaction of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I (2) with BF3·Et2O/Bu4NBr can give rise to 4 different products. Each of these products can be obtained selectively, under the appropriate reaction conditions., U reakciji α-4(20)-epoksi-5-O-meziltriacetiltaksicina I (2) sa bortrifluorid eteratom i tetrabutilamonijum-bromidom mogu nastati 4 različita proizvoda, u zavisnosti od reakcionih uslova. Svaki od ova 4 proizvoda se može dobiti selektivno, pod odgovarajućim reakcionim uslovima.",
publisher = "Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Reactions of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I induced by Bf3·Et2O/Bu4NBr, Reakcije α-4(20)-epoksi-5-O-meziltriacetiltaksicina I sa tetrabutilamonijum-bromidom u prisustvu bortrifluorid-eterata",
volume = "71",
number = "7",
pages = "705-711",
doi = "10.2298/JSC0607705F"
}

Ferjančić, Z., Matović, R., Čeković, Ž.,& Saičić, R. N.. (2006). Reactions of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I induced by Bf3·Et2O/Bu4NBr. in Journal of the Serbian Chemical Society
Serbian Chemical Society., 71(7), 705-711.
https://doi.org/10.2298/JSC0607705F

Ferjančić Z, Matović R, Čeković Ž, Saičić RN. Reactions of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I induced by Bf3·Et2O/Bu4NBr. in Journal of the Serbian Chemical Society. 2006;71(7):705-711.
doi:10.2298/JSC0607705F .

Ferjančić, Zorana, Matović, Radomir, Čeković, Živorad, Saičić, Radomir N., "Reactions of α-4(20)-epoxy-5-O-mesyltriacetyltaxicine I induced by Bf3·Et2O/Bu4NBr" in Journal of the Serbian Chemical Society, 71, no. 7 (2006):705-711,
https://doi.org/10.2298/JSC0607705F . .

TY  - JOUR
AU  - Ferjančić, Zorana
AU  - Matović, Radomir
AU  - Čeković, Živorad
AU  - Snyder, James P.
AU  - Saičić, Radomir N.
PY  - 2005
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2770
AB  - A C,D-seco-paclitaxel derivative 12 was prepared and tested for biological activity. The key step in the synthesis was a free radical fragmentation of the bicyclic tertiary alcohol 7 under the conditions of the hypobromite reaction. The compound 12 showed no activity in the tubulin test. (c) 2005 Elsevier Ltd. All rights reserved.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Tetrahedron Letters
T1  - Synthesis, biological evaluation, and modeling of a C,D-seco-taxoid
VL  - 46
IS  - 30
SP  - 5049
EP  - 5052
DO  - 10.1016/j.tetlet.2005.05.071
ER  - 

@article{
author = "Ferjančić, Zorana and Matović, Radomir and Čeković, Živorad and Snyder, James P. and Saičić, Radomir N.",
year = "2005",
abstract = "A C,D-seco-paclitaxel derivative 12 was prepared and tested for biological activity. The key step in the synthesis was a free radical fragmentation of the bicyclic tertiary alcohol 7 under the conditions of the hypobromite reaction. The compound 12 showed no activity in the tubulin test. (c) 2005 Elsevier Ltd. All rights reserved.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Tetrahedron Letters",
title = "Synthesis, biological evaluation, and modeling of a C,D-seco-taxoid",
volume = "46",
number = "30",
pages = "5049-5052",
doi = "10.1016/j.tetlet.2005.05.071"
}

Ferjančić, Z., Matović, R., Čeković, Ž., Snyder, J. P.,& Saičić, R. N.. (2005). Synthesis, biological evaluation, and modeling of a C,D-seco-taxoid. in Tetrahedron Letters
Oxford : Pergamon-Elsevier Science Ltd., 46(30), 5049-5052.
https://doi.org/10.1016/j.tetlet.2005.05.071

Ferjančić Z, Matović R, Čeković Ž, Snyder JP, Saičić RN. Synthesis, biological evaluation, and modeling of a C,D-seco-taxoid. in Tetrahedron Letters. 2005;46(30):5049-5052.
doi:10.1016/j.tetlet.2005.05.071 .

Ferjančić, Zorana, Matović, Radomir, Čeković, Živorad, Snyder, James P., Saičić, Radomir N., "Synthesis, biological evaluation, and modeling of a C,D-seco-taxoid" in Tetrahedron Letters, 46, no. 30 (2005):5049-5052,
https://doi.org/10.1016/j.tetlet.2005.05.071 . .