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Direkte Michael‐artige Addition von Si‐Gruppen an β‐Aryl‐α,β‐ungesättigte Carbonylverbindungen mit R 3 SiCl/Bu 2 Cu(CN)Li 2
Author(s) -
Amberg Willi,
Seebach Dieter
Publication year - 1990
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19901231227
Subject(s) - chemistry , chlorosilane , silylation , aryl , reagent , michael reaction , enone , double bond , addition reaction , medicinal chemistry , stereochemistry , organic chemistry , silicon , catalysis , alkyl
Direct Michael‐Type Addition of Si‐Groups to α,β‐Unsaturated p‐Aryl‐Substituted Enones with R 3 SiCl/Bu 2 Cu(CN)Li 2 ( E )‐5‐Benzylidene‐2‐ tert ‐butyl‐6‐methyl‐1,3‐dioxan‐4‐one ( 1 ) undergoes conjugative silylation (Me 3 Si, Et 3 Si, tBuMe 2 Si, Me 2 PhSi, products 2 ‐ 5) with the reagent specified in the title. The reaction is highly diastereoselective, with formal anti addition of R 3 Si and H from the Re ‐ and Si ‐face, respectively, of the exocyclic double bond [proof by NMR analysis and chemical correlation (cf. 6 and 7). A screening of various enone systems showed that this unprecedented Michael addition of Si groups with chlorosilane as a reagent, and under non‐reducing conditions occurs only if the x,p‐unsaturated carbonyl system bears an aryl group in the P‐position to give β‐aryl β‐silyl ketones (products 8‐ 15 ).