Copper(I)-catalyzed regio- and chemoselective single and double addition of nucleophilic silicon to propargylic chlorides and phosphates
Copper(I)-catalyzed propargylic substitution of linear precursors with (Me2PhSi)2Zn predominantly yields the γ isomer independent of the propargylic leaving group. The thus formed allenylic silane reacts regioselectively with another equivalent of (Me2PhSi) 2Zn, yielding a bifunctional building block with allylic and vinylic silicon groups. The reaction rates of both steps are well-balanced for chloride (γ:α ≥ 99:1) where the propargylic displacement occurs quantitatively prior to the addition step. Substitutions of α-branched propargylic phosphates are also reported.
Hazra, Chinmoy K.,Oestreich, Martin
p. 4010 - 4013
(2012/10/08)
Copper(I)-catalyzed regioselective propargylic substitution involving Si-B bond activation
The silicon nucleophile generated by copper(I)-catalyzed Si-B bond activation allows several γ-selective propargylic substitutions. The regioselectivity (γ:α ratio) is strongly dependent on the propargylic leaving group. Chloride is superior to oxygen leaving groups in linear substrates (γ:α > 99:1), and it is only the phosphate group that also shows promising regiocontrol (γ:α = 90:10). That leaving group produces superb γ-selectivity (γ:α > 99:1) in α-branched propargylic systems, and enantioenriched substrates react with excellent central-to-axial chirality transfer.
Vyas, Devendra J.,Hazra, Chinmoy K.,Oestreich, Martin
p. 4462 - 4465
(2011/10/08)
General and functional group-tolerable approach to allenylsilanes by rhodium-catalyzed coupling between propargylic carbonates and a silylboronate
[Chemical Equation Presented] The Rh-catalyzed coupling reaction between propargylic carbonates and a silylboronate afforded allenylsilanes with different substitution patterns In high yields. The reaction tolerates a variety of functional groups in propa
Ohmiya, Hirohisa,Ito, Hideto,Sawamura, Masaya
scheme or table
p. 5618 - 5620
(2010/03/05)
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