REDUCTION-ELIMINATION OF SOME VICINAL CYCLOALKYL CYANOHYDRIN DERIVATIVES - STEREOSELECTIVE SYNTHESIS OF CYCLOALKENES

The isomeric 2-cyano-2-methylcyclododecanols, 2-cyano-l, 2-dimethylcyclododecanols, and 2-cyano-l, 2-dimethylcyclohexanols were prepared from the corresponding cyano ketones. Reduction of the methanesulfonate, (methylthio)methyl, and (methanesulfonyl)methyl derivatives with lithium in ammonia (Li/NH3) or sodium naphthalenide (NaC10H8) gave rise to cis-and/or trans-1-methylcyclododecene, 1, 2-dimethylcyclododecene, and 1, 2-dimethylcyclohexene, respectively. The cyclododecyl systems showed a high preference for syn elimination with NaC10H8 whereas Li/NH3 gave products of both syn and anti elimination. The findings suggest a preferred coplanar transition state for the elimination reactions. © 1979, American Chemical Society. All rights reserved. © 1979, American Chemical Society. All rights reserved.