Convenient methods for preparing several 3 alpha ,5-cycloandrostanes have been developed in order to synthesize the phytoecdysteroid rubrosterone. Certain of their chemical transformations were studied.
Conversions of cyclopropyl carbinols (or their acetates) and ketones into homoallyl and γ-substituted ketone derivatives, respectively, are accomplished by trimethylsilyl tetrafluoroborate efficiently and under mild conditions.