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

摘要

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 allyl alcohol 2 in 65% yield with a diastereomeric excess greater than 98%. The treatment of Garner aldehyde 1 with CF_3CFBr_2 (3a) and CF_3CCl_3 (3b) in the presence of zinc powder and catalytic AlCl_3 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.