Assertion: acetyl chloride's step | /r/HasProperty | 97% ee
Facets:
Source sentences:
text: Protection of the alcohol with the sterically encumbered tert-butyl dimethylsilyl group allowed a diastereoselective copper(I)-mediated conjugate addition of methyl magnesium bromide to afford alcohol 56 after removal of the silyl protecting group.28 Mesylation and elimination under basic conditions then provided unsaturated ester 57 in 63% yield over four steps (97% ee).