Stereoselective Synthesis of Fluorinated Isoxazolidines and 2,3-Dihydroisoxazoles: A Cycloadditive Route to Enantiomerically Pure Amino Fluoro Alcohols
作者:Luca Bruché、Alberto Arnone、Pierfrancesco Bravo、Walter Panzeri、Cristina Pesenti、Fiorenza Viani
DOI:10.1002/(sici)1099-0690(199907)1999:7<1665::aid-ejoc1665>3.0.co;2-d
日期:1999.7
3-(Fluoroalkyl)isoxazolidines 6 and -2,3-dihydroisoxazoles 8 have been obtained in enantiomerically pure form with good diastereoselectivity by 1,3-dipolar cycloaddition of diethyl fumarate and dimethylacetylene dicarboxylate, respectively, to the chiral fluorinated nitrone (R)-5. The latter has been prepared from the β-fluoromethyl-β-oxo sulfoxide (RS)-1, by a synthetic sequence where the chiral and
3-(氟烷基)异恶唑烷 6 和 -2,3-二氢异恶唑 8 已通过富马酸二乙酯和二甲炔二甲酸二甲酯的 1,3-偶极环加成反应分别以对映体纯形式获得,具有良好的非对映选择性,与手性氟化硝酮(R)- 5. 后者是由 β-氟甲基-β-氧代亚砜 (RS)-1 通过合成序列制备的,其中手性和对映体纯亚磺酰基官能团作为可去除的手性来源。异恶唑烷6的还原开环然后以良好的产率提供氨基氟甲基二醇7。