Studies on intramolecular alkylation. IX. The synthesis of tricyclic dienones suitable for the synthesis of 13-hydroxygibberellins

Abstract

2-Hydroxy-6-methoxy-1,2,3,4-tetrahydro-2-naphthoic acid and its 8- methoxy isomer were converted into trichloroacetate and dichloroacetate derivatives and thence to diazoketones (2), (3), (12) and (13). The acid-catalysed cyclization of these substrates to the dienones (6), (7), (16) and (17), respectively, was then studied. The trichloroacetoxy derivatives gave the best yields of dienones.