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.