Asymmetric Synthesis of 2,2‐Difluorotetrahydrofurans through Palladium‐Catalyzed Formal [3+2] Cycloaddition
作者:Jun Liu、Longhui Yu、Changwu Zheng、Gang Zhao
DOI:10.1002/anie.202111376
日期:2021.10.25
The asymmetric synthesis of 2,2-difluorinated tetrahydrofurans was accomplished via enantioselective formal [3+2] cycloaddition catalyzed by palladium. The asymmetric reaction between gem-difluoroalkenes and racemic vinyl epoxides or vinylethylene carbonates resulted in the formation of enantioenriched 2,2-difluorotetrahydrofurans with an enantioselectivity up to 98 %. Notably, the reaction used the
2,2-二氟化四氢呋喃的不对称合成是通过钯催化的对映选择性正式[3+2]环加成反应完成的。嵴二氟烯烃与外消旋乙烯基环氧化物或乙烯基碳酸乙烯酯之间的不对称反应导致形成对映体富集的 2,2-二氟四氢呋喃,对映体选择性高达 98%。值得注意的是,该反应使用容易获得的 (R)-BINAP 作为低负载量的配体,并以中等至高产率产生多种二氟化产物。两种手性非对映异构体都可以在一个序列中获得。