[116399-78-1] · C7H15ClSi · (E)-(3-Chloro-1-methyl-1-propenyl)trimethylsilane · (MW 162.76)
(annulation reagent; alkylative equivalent of 3-buten-2-one; 3-oxobutyl synthon)
Alternate Name: (E)-1-chloro-3-trimethylsilyl-2-butene.
Physical Data: bp 92-94 °C/74 mmHg.
Solubility: freely sol organic solvents.
Form Supplied in: not commercially available.
Analysis of Reagent Purity: dH(CCl4) 0.0 (9H, s), 1.67 (3H, d, J 1.5 Hz), 3.93 (2H, d, J 7 Hz), 5.8 (1H, t of q, J 7 and 1.5 Hz).
Preparative Method: see 1-Iodo-3-trimethylsilyl-2-butene.
This reagent acts as the alkylative equivalent of 3-buten-2-one (Methyl Vinyl Ketone), permitting regiospecific enolate alkylation under nonequilibrating conditions. As a vinylsilane it can be converted,1 via the corresponding a,b-epoxy silane, into a 3-oxobutyl moiety, and hence used in an alkylative equivalent of Robinson annulation.2 Application of such methodology can be seen (eq 1) in the preparation of bicyclodecenones via the alkylation of dihydrocarvone with this reagent.3 Apart from this application, and its use in combination with potassium iodide4 (see 1-Iodo-3-trimethylsilyl-2-butene), it has seen little use so far.
Ernest W. Colvin
University of Glasgow, UK