Synthesis of benzopyran derivatives. XVIII. gem-Difluorination vs. 1,3-dithiolane-dihydro-1,4-dithiin rearrangement. The role of benzylic carbons
作者:Jozsef Jeko、Tibor Timar、Joseph C. Jaszberenyi
DOI:10.1021/jo00024a010
日期:1991.11
1,3-Dithiolanes bearing a phenyl or substituted aromatic group and a methyl (or methylene) group attached to C-2 cannot be gem-difluorinated with 1,3-dibromo-5,5-dimethylhydantoin (DBH) (or NBS) + HF/pyridine because a rapid 1,3-dithiolane-dihydro-1,4-dithiin rearrangement takes place instead.