Efficient and Convenient Route to (Z)-α,β-Unsaturated Difluoromethyl Ketones Based on the Reaction of 2,3,3-Trifluoro-1-tosyloxy-1-propenyllithium with Carbonyl Compounds
2,3,3-Trifluoro-1-tosyloxy-1-propenyllithium, generated from 2,3,3-trifluoro-1-propenyl p-toluenesulfonate with butyl-lithium, underwent coupling reaction with various carbonyl compounds to give good yields of 3,4,4-trifluoro-2-tosyloxy-2-butenyl alcohols, whose treatment with concentrated sulfuric acid at room temperature afforded the corresponding (Z)-α,β-unsaturated difluoromethyl ketones in good yields.