Reaction of lithium diphenylphosphonium di(methylide) with carbonic acid derivatives. A novel access to polyfunctional unsaturated esters and amides
✍ Scribed by Henri-Jean Cristau; Anne Perraud-Darcy; Yves Ribeill
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 678 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1042-7163
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The lithium diphenylphosphonium di(methylide) Ph~2~ P(CH~2~)~2~ Li 1 readily attacks cyclic carbonates, carbamates, and thiocarbamates, resulting in “pseudo‐acylation” products, after a ring‐opening step. Thus, new stabilized ylides are prepared, which can be used in situ as carbonyl olefination reagents towards aldehydes. This procedure is a new one‐pot method for the synthesis of (E)‐vinylic esters and amides, bearing a free ω‐hydroxyl group. When a thiocarbamate is the initial substrate for 1, a Michael‐type cyclization occurs, following the Wittig olefination, resulting in the one‐pot preparation of 7‐membered heterocycles.