Author(s) Xie, L.G.; Rogers, J.; Anastasiou, I.; Leitch, J.A.; Dixon, D.J.
Journal Org Lett
Date Published 2019 09 06

The catalytic reductive transformation of carboxylic esters into α-branched ethers is described. The procedure pivots on the chemoselective iridium-catalyzed hydrosilylation of ester and lactone functionality to afford a silyl acetal intermediate. Upon treatment with a Lewis acid, these hemilabile intermediates dissociate to form reactive oxocarbenium ions, which can be intercepted by allyltributyltin nucleophiles, resulting in the formation of valuable α-branched alkyl-alkyl ether derivatives. This reductive allylation procedure was found to be amenable to a range of carboxylic ester starting materials, and good chemoselectivity for ethyl over -butyl esters was demonstrated. Furthermore, downstream synthetic manipulation of α-amino acid-derived products led to the efficient formation of pyrrolidine, piperidine, and azepane frameworks.

DOI 10.1021/acs.orglett.9b02119
ISSN 1523-7052
Citation Org Lett. 2019;21(17):66636667.