SHORT, SIMPLE, STEREOCONTROLLED, STEROID-SYNTHESIS - (+/-)-11-OXOEQUILENIN METHYL-ETHER AND A NEW 9,11-SECO-13-ETHYL STEROID

An improved procedure has been developed for efficient preparation of 9,11-seco steroid 2b from 2-methyl-2-cyclopentenone in 85% yield and 99% stereochemical purity over three steps without chromatography. This high yield, almost double that previously reported by us, is achieved by using a magnesium instead of a lithium cuprate and ethyl iodoacetate instead of methyl bromoacetate. This procedure has been extended to stereocontrolled preparation of a new 9, 11-seco-13-ethyl steroid (5) of potential contraceptive value directly from 2-ethyl-2-cyclopentenone. 1H and 13C NMR data confirm that the incipient C,D-ring stereochemistry of seco steroids 2 and 5 is that of the natural steroids (i.e., trans). A high-yield HF-promoted Friedel-Crafts intramolecular acylation completes an efficient (50% overall yield) and stereocontrolled total synthesis of (±)-ll-oxoequilenin. © 1979, American Chemical Society. All rights reserved.