Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation
Abstract
Bromophilic attack by the transition metal carbonyl anion, [Re(CO)(5)]Na (pK(a) = 21.1), on 2-(1-bromoalkylidene)thiazolidin-4-ones is significantly faster than abstraction of an acidic lactam hydrogen (pK(a) similar to 17-18), when the generated carbanion is stabilized by an alpha-CN or alpha-PhCO group. The bromophilic reaction of 2-(1-bromoalkylidene)thiazolidin-4-one, having an alpha-CN electron-withdrawing group, resulted in formation of a new metallacyclic anionic complex. With less reactive vinyl bromides, containing an alpha-CONHPh or alpha-CO(2)Et group, only deprotonation is observed. The role of the metal carbonyl anion is highlighted by a comparison with the 9-methylfluorenide carbanion (pK(a) of 9-methylfluorene is 22.3), which reacts exclusively via a deprotonation pathway.
Keywords:
Halogenophilic reactions / Proton transfer / 2-(1-Bromoalkylidene)thiazolidin-4-ones / Metal carbonyl anionsSource:
Tetrahedron Letters, 2011, 52, 1, 29-33Publisher:
- Oxford : Pergamon-Elsevier Science Ltd
Funding / projects:
- Russian Federation - HLLI-4365.2010.3
- RAS - 1-OX
- Tiazolidni i sintetički analozi: reaktivnost, primena i biološka aktivnost (RS-142007)
DOI: 10.1016/j.tetlet.2010.10.112
ISSN: 0040-4039
WoS: 000286789100005
Scopus: 2-s2.0-78649872730
Collections
Institution/Community
IHTMTY - JOUR AU - Sazonov, P. K. AU - Džambaski, Zdravko AU - Shtern, M. M. AU - Marković, Rade AU - Beletskaya, I. P. PY - 2011 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/927 AB - Bromophilic attack by the transition metal carbonyl anion, [Re(CO)(5)]Na (pK(a) = 21.1), on 2-(1-bromoalkylidene)thiazolidin-4-ones is significantly faster than abstraction of an acidic lactam hydrogen (pK(a) similar to 17-18), when the generated carbanion is stabilized by an alpha-CN or alpha-PhCO group. The bromophilic reaction of 2-(1-bromoalkylidene)thiazolidin-4-one, having an alpha-CN electron-withdrawing group, resulted in formation of a new metallacyclic anionic complex. With less reactive vinyl bromides, containing an alpha-CONHPh or alpha-CO(2)Et group, only deprotonation is observed. The role of the metal carbonyl anion is highlighted by a comparison with the 9-methylfluorenide carbanion (pK(a) of 9-methylfluorene is 22.3), which reacts exclusively via a deprotonation pathway. PB - Oxford : Pergamon-Elsevier Science Ltd T2 - Tetrahedron Letters T1 - Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation VL - 52 IS - 1 SP - 29 EP - 33 DO - 10.1016/j.tetlet.2010.10.112 ER -
@article{ author = "Sazonov, P. K. and Džambaski, Zdravko and Shtern, M. M. and Marković, Rade and Beletskaya, I. P.", year = "2011", abstract = "Bromophilic attack by the transition metal carbonyl anion, [Re(CO)(5)]Na (pK(a) = 21.1), on 2-(1-bromoalkylidene)thiazolidin-4-ones is significantly faster than abstraction of an acidic lactam hydrogen (pK(a) similar to 17-18), when the generated carbanion is stabilized by an alpha-CN or alpha-PhCO group. The bromophilic reaction of 2-(1-bromoalkylidene)thiazolidin-4-one, having an alpha-CN electron-withdrawing group, resulted in formation of a new metallacyclic anionic complex. With less reactive vinyl bromides, containing an alpha-CONHPh or alpha-CO(2)Et group, only deprotonation is observed. The role of the metal carbonyl anion is highlighted by a comparison with the 9-methylfluorenide carbanion (pK(a) of 9-methylfluorene is 22.3), which reacts exclusively via a deprotonation pathway.", publisher = "Oxford : Pergamon-Elsevier Science Ltd", journal = "Tetrahedron Letters", title = "Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation", volume = "52", number = "1", pages = "29-33", doi = "10.1016/j.tetlet.2010.10.112" }
Sazonov, P. K., Džambaski, Z., Shtern, M. M., Marković, R.,& Beletskaya, I. P.. (2011). Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation. in Tetrahedron Letters Oxford : Pergamon-Elsevier Science Ltd., 52(1), 29-33. https://doi.org/10.1016/j.tetlet.2010.10.112
Sazonov PK, Džambaski Z, Shtern MM, Marković R, Beletskaya IP. Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation. in Tetrahedron Letters. 2011;52(1):29-33. doi:10.1016/j.tetlet.2010.10.112 .
Sazonov, P. K., Džambaski, Zdravko, Shtern, M. M., Marković, Rade, Beletskaya, I. P., "Reactions of transition metal carbonyl anions with 2-(1-bromoalkylidene)thiazolidin-4-ones: halogenophilic attack or deprotonation" in Tetrahedron Letters, 52, no. 1 (2011):29-33, https://doi.org/10.1016/j.tetlet.2010.10.112 . .