The reactions of organocuprates with various A17(20)-unsaturated steroid substrates leads to the stereocontrolled introduction of the side chain onto the steroid nucleus to give either desired C-20 epimer. The reaction of an £,-A17(2°)-16-keto steroid with lithium diisohexylcuprate leads to -face attack, giving exclusively a product having the "natural" 20/? chirality. This product was then converted to cholesterol. The reactions of either the E-17,20)-16a-pivalyloxy or the corresponding 16/3-pivaloyloxy steroid with lithium isohexylcyanocuprate each proceeded in a regio-and stereocontrolled manner. The former (16a) compound gave exclusively the "unnatural" 20S chirality while the latter (16/3) compound gave exclusively the "natural" 20.R chirality. The 20S compound was converted to 20-epicholesterol, and similarly, the 20R compound was converted to cholesterol. A result complementary to that of the pivalates ensued from the £-A17(20)-16a-jV-phenylcarbamoyl steroid, which was converted by the action of a presumed internal mixed cuprate to a compound having 20fi chirality.

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A male-produced aggregation pheromone, common to the rice weevil,Sitophilus oryzae, and the maize weevil,S. zeamais, was isolated and identified from hexane extracts of highly absorbent paper disks exposed individually to young virgin male weevils. A combination of preparative column and gas-liquid chromatography of disk extracts yielded purified natural pheromone. When analyzed by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry, the structure of the natural pheromone, "sitophilure," proved to be (R (*),S (*))-5-hydroxy-4-methyl-3-heptanone, of unknown enantiomeric composition. Synthetic racemic pheromone was highly attractive to males and females of both rice and maize weevils. In addition, both sexes of the granary weevil,S. granarius (L.) were attracted to the racemic preparation.

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