Iridium-catalyzed reductive allylation of esters

Journal article

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 tert-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.

Authors: Xie, L; Rogers, J; Anastasiou, I; Leitch, J; Dixon, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Organic letters More from this journal
• Volume: 21
• Issue: 17
• Pages: 6663-6667
• Publication date: 2019-08-09
• Acceptance date: 2019-08-09
• DOI: 10.1021/acs.orglett.9b02119
• EISSN: 1523-7052
• ISSN: 1523-7060
• Pmid: 31397155
• Language: English
• Keywords: FFR