Reactions of steroidal ketones with diazocyclopropane

Abstract

Diazocyclopropane reacts with pregn-4-ene-3,20-dione (7) to give a ring expansion product, spiro[cyclopropane-1,4′-A-homopregn-4a′-ene]-3′,20′-dione, and further reaction of this compound occurs with an excess of diazocyclopropane to give several cyclobutanone derivatives. Diazocyclopropane reacts with cholestan-3-one to give mainly cyclobutane derivatives, and with two pregnan-20-ones to give only cyclobutanone products. 20-Oxo-groups with electronegative substituents at C-17 react with diazocyclopropane to give only 20-spirocyclopropane derivatives.