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Stereoselectivity copper conjugate addition reactions

The prototype of copper-mediated conjugate addition reactions is the transformation of acceptor-substituted alkenes and alkynes into the corresponding adducts (Scheme 1). Whereas full control of the regio- and chemoselectivity in these Michael additions has been possible for a long time,3 the emphasis of the last decade has been put on the use of new copper reagents, the broadening of the substrate scope, and the control of the stereoselectivity of the conjugate addition. [Pg.502]

The configurational assignment thus rests solely on the stereochemical course of the copper-catalyzed conjugate addition of vinylmagnesium bromide to 7. a reaction process known to occur with trans stereoselectivity 106. [Pg.488]

Similar to the conjugate addition, the focus of the last decade has been put on the development of chiral copper catalysts for enantioselective S -substitutions of prochiral substrates.197,197a,197b 271,285 These represent a useful alternative for the preparation of those substitution products which cannot be obtained by anti-stereoselective copper-promoted or -catalyzed SN2 -substitution of chiral substrates (see Section 9.12.2.1.2). The first reported example for such a transformation is the reaction of the allyl acetate 333 with //-butylmagnesium bromide in the presence of 15 mol.% of the copper arenethiolate 334 which gave the substitution product 335 with exclusive y-selectivity and 50% ee (Equation (18)),286 286a... [Pg.549]


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See also in sourсe #XX -- [ Pg.9 ]




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Conjugate addition stereoselectivity

Conjugate reaction

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Conjugated reaction

Conjugative reactions

Copper addition reactions

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Copper conjugate addition

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