A facile preparation method for α,α-difluoroalkanecarboxylic acids and esters. A formal difluoromethylene insertion to alkanecarboxylic acids using radical reaction
the photoreaction of a series of Barton esters reacted with 1,1-dichloro-2,2-difluoroethene to give radical adducts as the major product accompanied with self-trapping products. Primary, secondary, tertiary, benzyl, and some unsaturated alkyl radicals as well as those with another functional group such as ether, carbonyl, and azide were applicable. Barton esters of diacids also afford 1:2 adducts with
通过一系列Barton酯的光反应生成的各种烷基自由基与1,1-二氯-2,2-二氟乙烯反应,生成自由基加合物作为主要产物,并伴有自捕获产物。伯,仲,叔,苄基和一些不饱和烷基以及具有另一官能团的那些如醚,羰基和叠氮化物是适用的。二元酸的巴顿酯还可以提供1:2加合物,以及少量的1:1加合物和双自陷产物(琥珀色情况除外)。这些加合物用AgNO 3 / H 2 O-THF水解为α,α-二氟链烷羧酸,并用AgNO 3甲醇水解。用/ MeOH制得相应的甲酯。将4-叠氮基-2,2-二氟丁酸和甲酯转化为二氟-GABA和二氟-γ-内酰胺。