Rapid and Slow Generation of 1-Trifluoromethylvinyllithium: Syntheses and Applications of CF3-Containing Allylic Alcohols, Allylic Amines, and Vinyl Ketones
作者:Ryo Nadano、Kohei Fuchibe、Masahiro Ikeda、Hiroki Takahashi、Junji Ichikawa
DOI:10.1002/asia.201000139
日期:——
1‐(Trifluoromethyl)vinylation is accomplished in two protocols by the in situ generation of thermally unstable 3,3,3‐trifluoroprop‐1‐en‐2‐yllithium (1): 1) a rapid lithium–halogen‐exchange reaction of 2‐bromo‐3,3,3‐trifluoroprop‐1‐ene (2) takes effect with sec‐BuLi at −105 °C to generate vinyllithium 1, which reacts with more reactive electrophiles, such as aldehydes and N‐tosylimines before its decomposition
1-(三氟甲基)乙烯基化是通过热不稳定的3,3,3-三氟丙-1-烯-2-基锂(1)的原位生成在两种方案中完成的:1)快速的锂-卤素交换反应为2 -溴3,3,3,3-三氟丙-1-烯(2)在sec -BuLi下于−105°C生效,生成乙烯基锂1,该乙烯基锂与更多的反应性亲电试剂(例如醛和N-甲苯基嘧啶)反应,然后分解,以高收率得到2-(三氟甲基)烯丙基醇和N- [2-(三氟甲基)烯丙基]磺酰胺;2)治疗的2与Ñ丁基锂在-100℃下导致的缓慢锂-卤素交换2,得到1和n BuLi的混合物。乙烯基锂1优先被困较低反应性的亲电子,如Ñ,ñ -dimethylamides在BF的存在3 ⋅OEt 2,得到1-以良好产率(三氟甲基)乙烯基酮。Pauson-Khand反应和Nazarov环化反应也证明了该产品对含CF 3的环稠合环戊烯酮的合成具有多功能性。