Enantioselective organocatalytic construction of hexahydropyrroloindole by means of α-alkylation of aldehydes leading to the total synthesis of (+)-gliocladin C.

12-step program: The combined use of cinchona alkaloid based amine and chiral phosphoric acid enabled the asymmetric alkylation reaction of 3-hydroxyoxindoles with aldehydes to give 3,3'-disubstituted oxindoles in excellent enantioselectivities, which allows for the enantioselective total synthesis of (+)-gliocladin C in 12 steps from 3-hydroxyoxindole with 19 % overall yield (see scheme; PMB = para-methoxybenzyl).