1，1—二卤代—1—烯烃的制备及其在有机合成中的应用

Recent Advances of 1,1-Dihalo-1-alkenes

1,1-二卤代-1-烯烃是有机化学中常见的合成片断,在合成化学中已得到了广泛的应用.该综述介绍了这一类化合物常见的制备方法以及反应的适用范围,并详细讨论了该类化合物在有机合成中的应用:(1)1,1-二卤代-1-烯烃在镁、有机锂、锌/溴化亚铜、二碘化钐、零价钯等金属或金属试剂作用下,发生α-消除反应生成烯基卡宾中间体的反应;(2)1,1-二卤代-1-烯烃在合成杂环以及核苷类似物等方面的应用.对于这类化合物在钯催化下的分子内(间)的偶联反应以及利用分子内的双环碳钯化反应,合成环状化合物等等方面的研究进展,也进行了详细的讨论.

1,1-Dihalo-1-alkenes are important synthetic intermediates, which provide convenient and versatile routes to polysubstituted alkenes and carbo- or hetero-cycles. In this paper, the preparations of 1,1-dihalo-1-alkenes were reviewed first. Secondly, the applications of 1,1-dihalo-1-alkenes in organic synthesis were discussed in detail: (1) the reaction of 1,1-dibromo-1-alkenes with metal or metal reagents forms alkylidene carbenes via a-elimination, which was followed by the common reactions of carbenes, such as 1,2-migration or 1,5-C-H insertion, etc. Metal species involved can be magnesium, organolithium, SmI2, stannyl anion and palladium; (2) the formation of 1-alkynyl bromides or alkynes via the elimination reaction; (3) regioselective H-abstraction-radical cyclization reaction; (4) inter- and intra-molecular cross-coupling reactions, reductive hydrolysis, and formal oxidative homologation under the catalysis of palladium. Recently, we have developed the bicyclic carbopalladation reaction, which affords the fused bicycles with different patterns in just one 'shot', such as 5,6-, 6,6-, 6,7-, and 7,7-bicycles. Possible mechanisms of these reactions were also discussed.