732302-19-1Relevant articles and documents
Lewis acid catalyzed allylboration: Discovery, optimization, and application to the formation of stereogenic quaternary carbon centers
Kennedy, Jason W. J.,Hall, Dennis G.
, p. 4412 - 4428 (2007/10/03)
A full account of the development of the first catalytic manifold for the additions of allylboronates to aldehydes is described. The thermal additions (both diastereospecific and enantioselective) of 2-carboxyester 3,3-disubstituted allylboronates 1 to both aromatic and aliphatic aldehydes give biologically and synthetically important exo-methylene butyrolactones 2 containing a β-quaternary carbon center. Although the thermal reaction requires 14 d at room temperature to reach completion, the presence of certain metal salts allows for a 12-16 h reaction while preserving the dia-stereospecificity observed in the uncatalyzed process. Preliminary mechanistic studies on the origin of the catalytic effect are described as well as stereoselective transformations of lactones 2 into cyclic and acyclic stereotriads with potential usefulness as synthetic intermediates.
