Catalytic Reactions of Metalloporphyrins. 3. Catalytic Modification of Hydroboration-Oxidation of Olefin with Rhodium(III) Porphyrin as Catalyst

Article abstract of DOI:10.1021/jo00388a037

(Octaethylporphyrinato)- or (tetraphenylporphyrinato)rhodium(III) chloride catalyzes the anti-Marcovnikov "hydration" of olefin with NaBH4 and O2 in THF. 1,5-Cyclooctadiene gives rise to cyclooctanol and 1,5-cyclooctanediol (in a ratio of approximately 1:2), and acetylenes are converted directly to alcohols under similar conditions.The initial step in the catalytic reaction of olefin is the hydride and borane transfers from BH4^- respectively to Rh^III porphyrin and olefin to give hydridorhodium (RhH) porphyrin and alkylborane.The RhH species undergoesoxidation with O2 back to Rh^III with concomitant oxidation of alkylborane with retention of configuration.This coupled oxidation of alkylborane is in competition with its nonstereospecific autooxidation without assistance of Rh-H.The present system provides a catalytic modification of hydroboration-oxidation of olefin in the presence of oxygen, as illustrated by the one-pot conversion of 1-methylcyclohexene to (E)-2-methylcyclohexanol with 100 percent regioselectivity and up to 97 percent stereoselectivity.

Full text of DOI:10.1021/jo00388a037

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Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.