hydrodefluorination reaction of trifluoromethylated alkenes to access terminal monofluoroalkenes. The use of LiAlH4 allowed the stereoselectivesynthesis of the terminal monofluoroalkenes in good to excellent yields with good to excellent diastereoselectivities. Mechanistic studies suggested a hydroalumination reaction followed by a stereoselective fluoride elimination.
1-tert-Butyl-1H-tetrazol-5-yl fluoromethyl sulfone (TBTSO2CH2F): a versatile fluoromethylidene synthon and its use in the synthesis of monofluorinated alkenes via Julia–Kocienski olefination
作者:Lingui Zhu、Chuanfa Ni、Yanchuan Zhao、Jinbo Hu
DOI:10.1016/j.tet.2010.04.113
日期:2010.7
1-tert-Butyl-1H-tetrazol-5-yl fluoromethyl sulfone (TBTSO2CH2F) has been developed as a new and efficient fluoromethylidene synthon for the synthesis of both terminal and internal monofluoroalkenes via Julia-Kocienski olefination reaction. The base-mediated reaction between TBTSO2CH2F and carbonyl compounds (aldehydes and ketones) provided terminal monofluoroalkenes in good yields with moderate E/Z selectivity. The dominance of E- or Z-fluoroalkenes could be controlled by selection of proper reaction solvent and temperature. TBTSO2CH2F reagent was also found to be readily a-alkylated, acylated, and phenylsulfonylated to give corresponding alpha-functionalized fluorosulfones, which could be used in the synthesis of alkyl-, acyl-, and phenylsulfonyl-substituted internal monofluoroalkenes via Julia-Kocienski olefination reactions. (C) 2010 Elsevier Ltd. All rights reserved.