A synthesis of (23R)- and (23S)-23H-calysterols 2a and 2b from pregnanoic ester 10 is reported. Alkylation of 10 with dibromide 19b, followed by reduction of the carboethyloxy group to a methyl group, afforded (Z)-vinylic bromide 22. Dibromocyclopropanation of 22 yielded the diastereomeric tribromocyclopropane derivatives 15c and 15d. The corresponding 3-hydroxy-5-ene 17c was transformed into 2a via