ANGULAR SUBSTITUENTS VIA CYCLOPROPANE DERIVATIVES OF BETA GAMMA-UNSATURATED KETONES

A method for introducing angular substituents in fused-ring systems is described. The base-catalyzed ring opening of β,γ-cyclopropyl ketones is facilitated by the presence of electron-withdrawing groups on the cyclopropane ring. The required cyclopropanes may be synthesized through the use of substituted carbenes. Substituents X and Y which promote ring opening of compound 1 are the following: X = CO2CH3, Y = H; X = Y = Cl; X = Y = Br. For the compound X = Cl, Y = H, no ring opening is observed. The reaction of chlorocarbene, generated from methyllithium and methylene chloride, with the Birch reduction products of naphthalene and tetralin is described. © 1969, American Chemical Society. All rights reserved.