Addition of aminoketene dithioacetals to α,β-unsaturated ketones. Synthesis and reactions of cyclohex-2-en-1,4-dione monodithioacetals
作者:Philip C. Bulman Page、Shaun A Harkin、Allan P. Marchington、Monique B. van Niel
DOI:10.1016/s0040-4020(01)89242-5
日期:1989.1
Aminoketene dithioacetals add to α,β-unsaturatedketones to give 1,5-diketones after hydrolytic work-up. Upon treatment with acid or base, these diketones suffer intramolecular aldol reactions yielding cyclohex-2-en-1,4-dione monodithioacetals, interesting and useful synthetic equivalents of cyclohex-2-en-1,4-diones which readily undergo conjugate addition and cycloaddition reactions.
Chemoselectivity as a Delineator of Cuprate Structure in Catalytic 1,4-Addition of Diorganozinc Reagents to Michael Acceptors
作者:Matthias Welker、Simon Woodward、Luis F. Veiros、Maria José Calhorda
DOI:10.1002/chem.200903310
日期:2010.5.17
of this SR‐protected 1,4‐benzoquinone has been compared with the behavior of the analogous OR‐protected acetal in copper‐catalyzed additions of ZnMe2 by using chiral phosphoramidite ligands. The activation energy for 1,4‐methylation of the latter OR‐acetals with ZnMe2 (>95 % ee) has been determined for two CuX2 pre‐catalysts (X=OAc, 12.2 kcal mol−1; X=OTf, 6.7 kcal mol−1; Tf=triflate). The dithioacetal