Platinum-Catalyzed Hydrosilylations of Internal Alkynes: Harnessing Substituent Effects to Achieve High Regioselectivity
作者:Douglas A. Rooke、Eric M. Ferreira
DOI:10.1002/anie.201108714
日期:2012.3.26
Rule of thumb: The high yielding title reaction is described with a focus on understanding the factors that govern the regioselectivity of the process (see scheme). Electronic, steric, and functional group properties all influence the selectivity, an understanding of which allows the selective formation of trisubstituted vinylsilanes, which are synthetically useful compounds for accessing stereodefined
Here we reported the iridium-catalyzed hydrosilylation of internalalkynes under simple and mild conditions. The intrinsic functional groups of alkyne substrates were disclosed to be crucial in facilitating both the hydrosilylation process and related regioselectivity owing to their coordination capability towards the iridium catalyst. Utilization of the steric trimethylsilyl-protected trihydroxysilane
Efficient Activation of 2-Iminomethylpyridine/Cobalt-Based Alkyne [2+2+2] Cycloaddition Catalyst by Addition of a Silver Salt
作者:Avijit Goswami、Taichi Ito、Sentaro Okamoto
DOI:10.1002/adsc.200700188
日期:2007.10.8
The addition of silver triflate (AgOTf) or silver hexafluoroantimonate (AgSbF6) significantly increased the activity of the 2-(arylimino)methylpyridine/cobalt(II) chloride hexahydrate (CoCl2⋅6 H2O)/zinc catalyst in alkyne cyclotrimerizations thereby accelerating the reaction and enabling the use of unactivated, simple internal alkynes as the monoyne substrate: The rate of reaction was found to be highly
Reductive addition of propargylic acetates to carbonyl compounds proceeded smoothly at room temperature by using SmI2 and a catalytic amount of Pd(PPh3)4 to give the corresponding acetylenic and/or allenic alcohols with appreciable selectivity. The method is useful especially for the preparation of tri- and tetrasubstituted allenic alcohols.
Reaction of Alkynyl- and Alkenyltrifluoroborates with Propargyldicobalt Cations: Alkynylation, Alkenylation, and Cyclopropanation Product Pathways
作者:Brent St Onge、S. Maryamdokht Taimoory、Jeffrey Battersby、John F. Trant、James R. Green
DOI:10.1021/acs.joc.1c02352
日期:2021.12.17
alkenyltrifluorobrates directly alkenylate, predominantly with the retention of stereochemistry. C-1-substituted alkenyltrifluoroborates alkenylate at C-2. Potassium vinyltrifluoroborate incorporates a cyclopropane at the site propargyl to alkynedicobalt. Computational analysis of these systems explains the differential modes of reactivity of alkenyltrifluoroborates and outlines the probable mechanisms for