Dibromomethane as one-carbon source in organic synthesis: a versatile methodology to prepare the cyclic and acyclic α-methylene or α-keto acid derivatives from the corresponding terminal alkenes
作者:Yung-Son Hon、Yu-Wei Liu、Cheng-Han Hsieh
DOI:10.1016/j.tet.2004.04.013
日期:2004.5
Ozonolysis of mono-substituted alkenes A-1 followed by reacting with a preheated mixture of CH2Br2–Et2NH affords α-substituted acroleins A-2 in good yields. Under very mild reaction conditions, these α-substituted acroleins A-2 can be easily converted to α-methylene esters A-4, which could be further converted to the corresponding α-keto esters A-5. This methodology can be also applied to the preparation
将单取代的烯烃A - 1进行臭氧分解,然后与CH 2 Br 2 -Et 2 NH的预热混合物反应,可得到高产率的α-取代的丙烯醛A - 2。在非常温和的反应条件下,这些α-取代的丙烯醛A - 2可以轻松转化为α-亚甲基酯A - 4,然后可以进一步转化为相应的α-酮酸酯A - 5。该方法还可用于制备α-亚甲基内酯B - 4,具有各种环尺寸的α-亚甲基内酰胺和α-酮内酯B - 5。