Cu-Catalyzed Enantioselective Borylative Desymmetrization of 1-Vinyl Cyclobutanols and Axial-to-Point Chirality Transfer in a Diastereoconvergent/Stereoretentive Allylation Scenery

Identifier:  imarina:9389463

Handle: https://hdl.handle.net/20.500.11797/imarina9389463

Authors:  Hurtado, Josebe; Iragorri, Nerea; Reyes, Efraim; Vicario, Jose L; Fernandez, Elena

Abstract:
Cu-catalyzed asymmetric allylic borylation of 3,3'-disubstituted 1-vinylcyclobutan-1-ols renders axially chiral allylborane systems, with high asymmetric induction for both enantiomers, by precise selection of the cis or trans substrate. The enantioenriched alkylidenecyclobutanes served as chiral platform to prove the conceptually challenging transference of the axial-to-point chirality through two new stereocenters and one pseudoasymmetric carbon generated via diastereoconvergent allylation of aldehydes, without enantioselective erosion. Desymmetrization of 1-vinylcyclobutanols via asymmetric Cu-catalyzed borylation creates axially chiral allylboranes in high enantiomeric ratio for both enantiomers. The axial-to-chiral transfer is possible through diastereoconvergent allylation with aldehydes, proving the preference for the same diastereoisomeric homoallylic alcohol, creating two new stereocenters and one pseudoasymemtric center with stereoretention for both enantiomers. image