Reaction of 5-Chloroalkyl-3-phenyl-4,5-dihydroisoxazoles with strong base. An unexpected new synthesis of the 2-Oxa-3-azabicyclo[3,1,0]hex-3-ene ring system

Reaction of 5-chloromethyl-3-phenyl-4,5-dihydroisoxazole with potassium t-butoxide in dimethyl sulphoxide gives 4-phenyl-2-oxa-3-azabicyclo[3,1,0]hex-3-ene in high yield and reaction of the 5-(1'-chloroethyl) homologue gives high yields of the diastereoisomeric 6-methyl derivatives of the bicyclic system. Some unsuccessful attempts to convert these bicyclic compounds into substituted cyclo-propanols and cyclopropenes are described.