Highly(≥98%) Selective Trisubstituted Alkene Synthesis of Wide Applicability via Fluoride-Promoted Pd-Catalyzed Cross-Coupling of Alkenylboranes.

ABSTRACT: (Z)-β-bromo-1-propenyl(pinacol)borane(4), recently made available in 85% yield as a ≥98% isomerically pure compound via bromoboration of 1-propyne, has been converted to β-alkyl-, aryl-, and alkenyl-substituted (Z)-2-methyl-1-alkenyl(pinacol)boranes(2a) in ca. 75% yield based on propyne via Pd-catalyzed Negishi alkenylation with suitable organozinc bromide. The previously sluggish and modest-yielding Suzuki alkenylation of β,β-disubstituted alkenylboranes has been significantly promoted by fluorides, especially nBu₄NF(TBAF) or CsF to give trisubstituted alkenes, i.e., (Z)-β-Me-substituted 3-i-3-xi and (E)-β-Ph-substituted 2b-i and 2b-ii. In all cases, eac

SUBMITTER: Negishi EI 

PROVIDER: S-EPMC3747006 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature