regioselective cycloaddition to benzonitrile oxide. In the reaction with the less reactive mesitonitrile oxide the sulfur dioxide deriving from the dimerization of the dipolarophile causes a catalytic decomposition of the nitrileoxide, which competes with the cycloaddition. Benzothiophene-1,1-dioxide and the vinyl sulfone system of 2,3-dihydrothiophene-1,1-dioxide and nitrileoxides with lower regioselectivity
Regioselective synthesis of 3-acylated 2,5-dihydrothiophene S,S-dioxides via ultrasound-promoted allylzincation of 3-bromo-2,3-dihydrothiophene S,S-dioxide
作者:Hsi-Hwa Tso、Ta-shue Chou、Su Chun Hung
DOI:10.1039/c39870001552
日期:——
3-Acylated2,5-dihydrothiopheneS,S-dioxides were synthesized from 3-hydroxyalkylated 2,3-dihydrothiophene S,S-dioxides, prepared highly regioselectivelyviaultrasound-promotedallylzincation of 3-bromo-2,3-dihydro-thiophene S,S-dioxide.
The Diels-Alderreactions of N-phenylmaleimide and new chiral 2-sulfinylbutadienes, which were prepared from , produced cycloadducts up to 99% d.e. in the presence of LiClO4 at ambient temperature. On the other hand, we found the facialselectivity of the cycloaddtion changed greatly among various Lewis acids.