Fluorine-containing optically active allylic alcohols: preparation and Claisen rearrangement as a new entry to highly functionalized fluorinated amino alcohol derivatives

Abstract

The reaction of Garner aldehyde 1 with 2-bromo-3,3,3-trifluoropropene in the presence of Zn–Ag couple gave the fluorine-containing, optically active allylic alcohol 2 in 65% yield with a diastereomeric excess greater than 98%. The treatment of Garner aldehyde 1 with CF₃CFBr₂ (3a) and CF₃CCl₃ (3b) in the presence of zinc powder and catalytic AlCl₃ highly diastereoselectively afforded 4a and 4b, respectively, in moderate yield. The orthoester Claisen rearrangement of 4a, b and 2 provided a new way to highly functionalized amino alcohol derivatives 6a–f containing a limited number of fluorine atoms.