Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies

Douglas C. Behenna, Justin T. Mohr, Nathaniel H. Sherden, Smaranda C. Marinescu, Andrew M. Harned, Kousuke Tani, Masaki Seto, Sandy Ma, Zoltán Novák, Michael R. Krout, Ryan M. McFadden, Jennifer L. Roizen, John A. Enquist, David E. White, Samantha R. Levine, Krastina V. Petrova, Akihiko Iwashita, Scott C. Virgil, Brian M. Stoltz

Research output: Contribution to journalArticlepeer-review

136 Scopus citations

Abstract

α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursor: enol carbonates, enol silanes, and racemic β-ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target-directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner-sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center.
Original languageEnglish (US)
Pages (from-to)14199-14223
Number of pages25
JournalChemistry - A European Journal
Volume17
Issue number50
DOIs
StatePublished - Nov 14 2011
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-11-006-02
Acknowledgements: This publication is based on work supported by award number KUS-11-006-02, made by the King Abdullah University of Science and Technology (KAUST). We thank the NIH-NIGMS (R01 GM080269-01 and postdoctoral fellowships to AMH and DEW), The Fannie and John Hertz Foundation (predoctoral fellowship to DCB), Eli Lilly (predoctoral fellowships to JTM, RMM, and MRK), Ono Pharmaceutical Co., Ltd. (postdoctoral fellowship to KT), The Hungarian-American Enterprise Scholarship Fund (postdoctoral fellowship to ZN), Takeda Pharmaceutical Co., Ltd. (postdoctoral fellowship to MS), The California Tobacco-Related Disease Research Program of the University of California (predoctoral fellowship to JLR, grant number 14DT-0004), Marcella R. Bonsall and the Dalton Fund (undergraduate fellowships to SRL), the Caltech Amgen Scholars Program (undergraduate fellowship to KVP), The 21st Century COE Program for Frontiers in Fundamental Chemistry from the Ministry of Education, Culture, Sports, Science and Technology, Japan (financial support to AI), the A. P. Sloan Foundation, Research Corporation, the Dreyfus Foundation, Bristol-Myers Squibb, GlaxoSmithKline, Johnson and Johnson, Amgen, Merck Research Laboratories, Pfizer, Novartis, Roche, Abbott Laboratories, Boehringer-Ingelheim, AstraZeneca, and Caltech for financial support. We acknowledge Dr. Mike Day and Larry Henling for assistance with X-ray crystallography. Ruthenium olefin metathesis catalysts were generously donated by Materia.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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