1241903-38-7Relevant academic research and scientific papers
Iron-Catalyzed e?Selective dehydrogenative borylation of vinylarenes with pinacolborane
Wang, Chao,Wu, Caizhi,Ge, Shaozhong
, p. 7585 - 7589 (2018/05/23)
We report the dehydrogenative borylation of vinylarenes with pinacolborane (HBpin) catalyzed by an iron(0) complex “(PMe3)4Fe”. A variety of monosubstituted and disubstituted vinylarenes underwent this iron-catalyzed transformation, affording E-vinyl boronate esters (VBEs) selectively in hi h ields. In addition we coupled this iron-catal zed dehydrogenative borylation with further transformations of the resulting vinyl boronate esters and developed various one-pot procedures for the functionalization of the vinylic C?H bonds in vinylarenes. Mechanistic studies reveal that this Fe-catalyzed reaction proceeds through syn-insertion of vinylarenes into a Fe-boryl species followed by β-hydrogen elimination from a syn coplanar conformation of the borylalkyl iron intermediate.
Arylethyne bromoboration-Negishi coupling route to E- Or Z-aryl-substituted trisubstituted alkenes of ≥ 98% isomeric purity. New horizon in the highly selective synthesis of trisubstituted alkenes
Wang, Chao,Xu, Zhaoqing,Tobrman, Tomas,Negishi, Ei-Ichi
supporting information; experimental part, p. 627 - 631 (2010/06/21)
The hitherto unprecedented palladiumcatalyzed cross-coupling of (Z)-β-bromo-β-arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri-tert-butylphosphine) palladium or dichloro[N,N-bis-(2,6-diisopropylphenyl)imidazol-2-yl](m- chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ≥ 98% stereo- and regioselectivity, while suppressing the otherwise dominant β-debromoboration. Together with the alkylethyne-based protocols, the alkyne bromoboration-Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access.
