Utilizing terminal alkenes in asymmetric synthesis: Development and application of efficient diboration/cross-coupling cascades.

摘要

The first highly enantioselective diboration of unfunctionalized terminal alkenes has been developed using a platinum-phosphonite complex. This transformation produces versatile 1,2-bis(boronate)esters that can manipulated chemoselectively to generate a pletheroa of enantioenriched structural motifs. When combined with an appropriate palladium catalyst, the diboration product undergoes an efficient alkyl boron cross-coupling with aryl and vinyl electrophiles producing a wide range of enantioenriched homobenzylic and homoallylic boronates. Alternatively, when the 1,2-bis(boronate)ester diboration product contains an adjacent Z-olefin (derived from diboration of cis-1,3-dienes), allylation to aldehydes can be achieved delivering the syn-diastereomer of product exclusively with excellent chirality transfer. Notably, the products obtained from the two described reactions contain an additional boronate moiety, which can be further functionalized through known carbon-boron bond transformations.