Oxidative cyclization of diols derived from 1,5-dienes:: Formation of enantiopure cis-tetrahydrofurans by using catalytic osmium tetroxide;: Formal synthesis of (+)-cis-solamin

(Chemical Equation Presented) High yields and high levels of stereocontrol are observed in the oxidative cyclization of vicinal diols using catalytic amounts of a transition metal (see scheme; TFA = trifluoroacetic acid). The product stereochemistry is controlled completely by the starting material, and, importantly, single enantiomers can be accessed readily. The reaction sequence is demonstrated in a very short formal synthesis of the natural product (+)-cis-solamin. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.