title: Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination.
abstract: A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Udaya Sree
authors.initials: US
authors.lastname: Dakarapu
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Apparao
authors.initials: A
authors.lastname: Bokka
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Parham
authors.initials: P
authors.lastname: Asgari
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Trog
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Yuanda
authors.initials: Y
authors.lastname: Hua
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Hiep H
authors.initials: HH
authors.lastname: Nguyen
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Nawal
authors.initials: N
authors.lastname: Rahman
authors.affiliation: Department of Chemistry and Biochemistry, University of Texas at Arlington , Arlington, Texas 76019, United States.
authors.forename: Junha
authors.initials: J
authors.lastname: Jeon