Regiospecific Carboxylation of Certain Methoxylated 2-Tetralones

Abstract

As a part of an ongoing synthetic program, certain aromatic ringmethoxylated tetralins, bearing synthetically useful functional groups at positions 2 and 3, were required. The literature¹ revealed that treatment of 6-methoxy-2-tetralone with NaH and dimethyl carbonate gave exclusive carbomethoylation at position 1. However, treatment of 2-tetralone and of 5-methoxy-2-tetralone with magnesium methoxy carbonate (“MMC”) followed by esterification with diazomethane was reported² go give the 3-carbomethoxy product (la, lb) exclusively, although in low (12 and 26%, respectively) yield. The use of MMC in regiospecific carboxylation of certain acylic ketones has also been reported³.