Regiochemical and stereochemical studies on halogen-induced ring expansions of unsaturated episulfides
摘要:
The reactions of unsaturated episulfides with bromine and iodine have been studied. Initially produced in the reaction is a ring opened sulfenyl halide intermediate, which in the presence of the carbon-carbon double bond or triple bond cyclizes to beta,beta'-dihalo sulfide cycloadducts. The regiochemistry and relative stereochemistry of these cyclizations have been examined as a function of the length of the tether between the episulfide moiety and the unsaturated functionality, the presence of alkyl substituents, and the type of unsaturation. A discussion of the mechanistic and stereochemical features of the ring-expansion process is presented.
Synthesis and some chemical conversions of acetylenic derivatives of 1,4-dioxane
作者:M. G. Veliev、M. I. Shatirova、O. V. Askerov
DOI:10.1007/s10593-010-0406-4
日期:2009.10
synthesizing acetylenic derivatives of 1,4-dioxane in high yield by the interaction of glycidyl ethers of acetylenic alcohols with ethylene bromohydrin in the presence of boron trifluoride etherate. Dehydrobromination of the corresponding bromohydrin was then carried out in the presence of metallic sodium in absolute diethyl ether. Acetylenic derivatives of 1,4-dioxane enter into hydrosilylation, aminomethylation