S. Yamaguchi, A. Arisawa, Naoko Katoh
Sep 15, 1997
Citations
0
Influential Citations
8
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
The stereochemistry was studied concerning the ring expansion of some 2-isopropenylcyclopropane-1-carbonyl compounds to 2,5-dihydro-3-methyloxepin derivatives. The LAH reduction of dimethyl 2-isopropenylcyclopropane-1,1-dicarboxylate (1aa) gave the corresponding diol, and a subsequent Swern oxidation gave a seven-membered 4,7-dihydro-6-methyloxepin-3-carbaldehyde. A DIBAL reduction of 1aa gave two isomeric hydroxymethyl carboxylic esters, and a subsequent Swern oxidation of methyl 1-hydroxymethyl-t-2-isopropenylcyclopropane-r-1-carboxylate caused a ring expansion to give methyl 4,7-dihydro-6-methyloxepin-3-carboxylate; however, a similar Swern oxidation of methyl 1-hydroxymethyl-c-2-isopropenyl-cyclopropane-r-1-carboxylate caused no ring expansion to give methyl 1-formyl-c-2-isopropenylcyclopropane-r-1-carboxylate.