Journal of Organic Chemistry 2003-10-31

Double diastereoselection in aldol reactions mediated by dicyclohexylchloroborane between L-erythrulose derivatives and chiral aldehydes. The Felkin-Anh versus Cornforth dichotomy.

J Alberto Marco, Miguel Carda, Santiago Díaz-Oltra, Juan Murga, Eva Falomir, Harald Roeper

Index: J. Org. Chem. 68 , 8577-8582, (2003)

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Abstract

Both matched and mismatched diastereoselections have been observed in aldol reactions of the B,B-dicyclohexylboron enolate of a protected l-erythrulose derivative with a range of chiral aldehydes. The stereochemical outcome of reactions with alpha-methyl aldehydes can be adequately explained within the Felkin-Anh paradigm. In the case of alpha-oxygenated aldehydes, however, strict adherence to this model does not allow for a satisfactory account of the observed results. In such cases, the Cornforth model provides a much better explanation.