STEROIDAL CYCLOBUTANONES .4. HETEROCYCLIC SPIROANNULATION OF 5-ALPHA-CHOLESTAN-3-ONE - STEREOSPECIFIC BECKMANN REARRANGEMENT OF STEROIDAL 3-SPIROCYCLOBUTANONE OXIMES

Diastereomeric cholestane-3,3'-spiro-2',2'-dichlorocyclobutanones 1 an d 2 served as starting materials for the synthesis of related heterocy clic spirane derivatives. Thus, diastereomeric 5alpha-cholestane-3,3'- spiropyrrolidin-5'-one (10, 11), -3'-spiro-gamma-lactone (12, 16), and -3'-spirotetrahydrofuran (14, 8) are described. The spirocyclobutanon e oximes (E)-4 and (Z)-5 and their O-acetyl and O-benzoyl derivatives 6, 7 and 8, 9 are also prepared, It has been shown that the Beckmann r earrangement of the spirocyclobutanone oximes 4 and 5 proceeds stereos pecifically with exclusive anti migration. The stereochemistry of the spiro compounds is assigned on the basis of the H-1- and C-13-NMR spec tral data.