Hydroboration. 83. Asymmetric hydroboration of representative cis disubstituted and heterocyclic olefins with dicaranylboranes of high enantiomeric purity

…, JVNV Prasad, M Zaidlewicz

Index: Brown, Herbert C.; Prasad, J.V.N. Vara; Zaidlewicz, Marek Journal of Organic Chemistry, 1988 , vol. 53, # 13 p. 2911 - 2916

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Citation Number: 36

Abstract

Dicaranylboranes (2-dIcr2BH and 4-dIcr2BH) are prepared by the reaction of borane-methyl sulfide with (+)-2-and (+)-3-carene, respectively. The reagents readily hydroborate prochiral cis disubstituted olefins to yield the corresponding trialkylboranes, which, upon oxidation, give chiral alcohols of 77-93% ee (2-dIcr2BH) and 36-75% ee (4-dIcr2BH). 2-dIcr, BH and 4- dIcr2BH convert &-alkenes into alcohols of the opposite absolute configurations. The ...