- 著者
- Oh Ken Fuchibe Kohei Yokota Misaki Ichikawa Junji
- 出版者
- Georg Thieme Verlag
- 雑誌
- Synthesis (ISSN:00397881)
- 巻号頁・発行日
- vol.2012, no.6, pp.857-861, 2012-03
- 被引用文献数
- 16
Two methods for the difluorovinylidenation of carbonyl compounds have been developed to synthesize 1,1-difluoroallenes bearing various substituents. The reaction of 1-bromo-2,2-difluorovinyllithium, generated from 1,1-dibromo-2,2-difluoroethylene and n-butyllithium, with aldehydes or ketones, and subsequent acetylation, gives 2-bromo-3,3-difluoroallylic acetates. Elimination of these acetates with n-butyllithium affords 1,1-difluoroallenes in high yield. 3,3-Difluoro-2-iodoallylic acetates are similarly prepared from aldehydes or ketones on treatment with 2,2-difluoro-1-iodovinyllithium, generated from 1,1,1-trifluoro-2-iodoethane and lithium diisopropylamide, followed by acetylation. These acetates readily undergo elimination with zinc metal to afford 1,1-difluoroallenes in high yield.