Reactions of 2-chloro-NN-diethyl-1,1,2-trifluoroethylamine with alcohols. Part I. Preparation of 2β- and 4β-fluorogibberellins

Abstract

The allylic 2β-hydroxy-group in esters of gibberellic acid (9) reacts with 2-chloro-NN-diethyl-1,1,2-trifluoro-ethylamine to give the corresponding esters of 2β-fluoro-4aα,7-dihydroxy-1β-methyl-8-methylenegibb-3-ene-1α, 10β-dicarboxylic acid 1,4a-lactone (5) and its allylic isomer 4β-fluoro-4aα,7-dihydroxy-1β-methyl-8-methylenegibb-2-ene-1α,10β-dicarboxylic acid 1,4a-lactone (14). The fluoro-acids (5) and (14) themselves were obtained by de-esterification of the corresponding p-bromophenacyl esters (7) and (15).