title: Double diastereoselection in aldol reactions mediated by dicyclohexylchloroborane between chiral aldehydes and a chiral ethyl ketone derived from L-erythrulose. synthesis of a C1-C9 fragment of the structure of the antifungal metabolite soraphen A1alpha.
abstract: [Chemical reaction: See text] Both matched and mismatched diastereoselections have been observed in the aldol reactions of a range of chiral aldehydes with the dicyclohexylboron enolate of a chiral ethyl ketone related to L-erythrulose. As was previously observed in the corresponding aldol reactions with L-erythrulose derivatives, the Felkin-Anh model provides an adequate explanation for the stereochemical outcome of reactions with chiral alpha-methyl aldehydes. However, a satisfactory account of the results observed with alpha-oxygenated aldehydes was only possible with the Cornforth model. As a practical application of the methodology described herein, a C1-C9 fragment of the structure of the antifungal macrolide soraphen A1alpha has been prepared in a convergent and stereoselective way.
authors.affiliation: Departamento de Química Inorgánica y Orgánica, and Servicios Centrales de Instrumentación, Universidad Jaume I, E-12080 Castellón, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Díaz-Oltra
authors.forename: Juan
authors.initials: J
authors.lastname: Murga
authors.forename: Eva
authors.initials: E
authors.lastname: Falomir
authors.forename: Miguel
authors.initials: M
authors.lastname: Carda
authors.forename: Gabriel
authors.initials: G
authors.lastname: Peris
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Marco