jo8b02613_si_001.pdf (18.24 MB)
Substrate-Controlled Direct α‑Stereoselective Synthesis of Deoxyglycosides from Glycals Using B(C6F5)3 as Catalyst
journal contributionposted on 2019-02-01, 00:00 authored by Abhijit Sau, Carlos Palo-Nieto, M. Carmen Galan
B(C6F5)3 enables the metal-free unprecedented substrate-controlled direct α-stereoselective synthesis of deoxyglycosides from glycals. 2,3-Unsaturated α-O-glycoside products are obtained with deactivated glycals at 75 °C in the presence of the catalyst, while 2-deoxyglycosides are formed using activated glycals that bear no leaving group at C-3 at lower temperatures. The reaction proceeds in good to excellent yields via concomitant borane activation of glycal donor and nucleophile acceptor. The method is exemplified with the synthesis of a series of rare and biologically relevant glycoside analogues.