Copper-catalyzed diastereoselective synthesis of β-boryl-α-quaternary carbon carboxylic esters

Abstract

Cu(i)-Catalyzed diastereoselective carboboration of α-alkyl-substituted α,β-unsaturated carboxylic esters to produce β-boryl-α-quaternary carbon esters was developed.

First-Row d-Block Element-Catalyzed Carbon–Boron Bond Formation and Related Processes

“…In this case, the diastereoselectivity of the reaction is proposed to proceed through a copper(I) enolate intermediate (72), in which attachment of the electrophile occurs on the less hindered side (Scheme 158). 591 A thorough study by Hoveyda et al shed light on the mechanistic aspects, efficiency, and enantioselectivity of transformations involving a copper catalyst, alkene, B 2 pin 2 , and allyl electrophile (Scheme 159). 592 Borylcupration of the styrene moiety generates an organocopper intermediate that is trapped by an allyl phosphate.…”

Copper-Catalyzed Borylative Difunctionalization of π-Systems

“…The Zhong group set out to develop this method using highly substituted acrylates (Scheme ). While the major side product observed was protodemetalation ( 37 ), the desired difunctionalized products were obtained in good yields ( 35 ). Impressively, the enolate showed high diasterocontrol during the alkylation process resulting in anti -difunctionalization, arising from the intermediate ( 36 ) undergoing addition from the opposite face of the R 1 substituent.…”

Access to Stereodefined Multifunctionalized β,γ‐Unsaturated Ketones via Chemo‐, Regio‐ and Diastereoselective Copper‐Catalyzed Diborylation of Cross‐Conjugated Enynones†

“…[12] New methods for their preparation have continuously attracted interests from the synthetic community. [13] Particularly, selective borylation reactions of unsaturated carbonyls [14] and enynes [15] have been developed respectively as practical methods in making organoboron compounds in recent years. However, with the combination of these functional groups, such as cross-conjugated enynones, the issues associated with chemo-, regio-and stereoselectivity in borylation reaction have remained elusive.…”