Reformatsky Reaction of Methyl 1-Bromocycloalkanecarboxylates with α-Dicarbonyl Compounds

Abstract

Reformatsky reactions of methyl 1-bromocyclohexanecarboxylate and methyl 1-bromocyclo-pentanecarboxylate with 2-aryl-2-oxoacetaldehydes involve both carbonyl groups of the latter and result in formation of 3a-aryl-3,3 : 6,6-bis(pentamethylene)- and 3a-aryl-3,3 : 6,6-bis(tetramethylene)tetrahydrofuro-[3,2-b]furan-2,5-diones. The reaction with 2-(2,4-dimethylphenyl)-2-oxoacetaldehyde gives acyclic products, methyl 1-[1-hydroxy-2-(2,4-dimethylphenyl)-2-oxoethyl]cyclohexanecarboxylate and methyl 1-[1-hydroxy-2-(2,4-dimethylphenyl)-2-oxoethyl]cyclopentanecarboxylate, while with benzil methyl 1-(4-hydroxy-1-oxo-3,4-diphenyl-2-oxaspiro[4.5]dec-3-yl)cyclohexanecarboxylate and methyl 1-(4-hydroxy-1-oxo-3,4-diphenyl-2-oxaspiro[4.4]non-3-yl)cyclopentanecarboxylate are obtained.