Organocatalytic Asymmetric Sulfa-Michael Addition of Thiols to 4,4,4-Trifluorocrotonates
摘要:
The first asymmetric sulfa-Michael addition of thiols to 4,4,4-trifluorocrotonates for the construction of a stereogenic center bearing a unique trifluoromethyl group and a sulfur atom has been achieved in high yields and excellent enantioselectivities with a 1 mol % bifunctional organocatalyst. Subsequent transformation led to the expedient preparation of enantioenriched thiochroman-4-one and the key intermediate of the potent inhibitor of MMP-3, (R)-gamma-trifluoromethyl gamma-sulfone hydroxamate.
Two ‘unnatural’ derivatives of shikimic acid, cis- and trans-6-trifluoromethylshikimicacid, have been synthesized in their racemic forms via the base-promoted opening of furan Diels–Alder adducts bearing a CF3 group. The relative stereochemistry of the trans-diastereoisomer has been confirmed by an X-ray analysis of its t-butyl ester.
Organocatalytic Asymmetric Sulfa-Michael Addition of Thiols to 4,4,4-Trifluorocrotonates
作者:Xiu-Qin Dong、Xin Fang、Chun-Jiang Wang
DOI:10.1021/ol201766k
日期:2011.8.19
The first asymmetric sulfa-Michael addition of thiols to 4,4,4-trifluorocrotonates for the construction of a stereogenic center bearing a unique trifluoromethyl group and a sulfur atom has been achieved in high yields and excellent enantioselectivities with a 1 mol % bifunctional organocatalyst. Subsequent transformation led to the expedient preparation of enantioenriched thiochroman-4-one and the key intermediate of the potent inhibitor of MMP-3, (R)-gamma-trifluoromethyl gamma-sulfone hydroxamate.
Improved synthesis of 3-(trifluoromethyl)pyrrole
作者:J. Leroy
DOI:10.1016/s0022-1139(00)82239-3
日期:1991.6
This paper describes a synthesis of 3-(trifluoromethyl)pyrrole from t-butyl (E)-4,4,4-trifluorobutenoate and tosylmethylisocyanide via decarboxylation in 45% yield of 4-(lrifluoromethyl) pyrrole-3-carboxylicacid over barium-promoted copper chromite in quinoline.