66132-89-6Relevant academic research and scientific papers
Synthesis and reactivity of iron carbonyl complexes of α,β-unsaturated acyl silanes
Thomas, Susan E.,Tustin, Gary J.,Ibbotson, Arthur
, p. 7629 - 7640 (2007/10/02)
2-Trimethylsilyl-1-oxa-1,3-butadiene (7) reacts with Fe2(CO)9 to form an unstable tetracarbonyliron (0) complex (8) whereas 2-trimethylsilyl-4-phenyl-1-oxa- 1-oxa-1,3-butadiene (9) and 2-(tert-butyldimethylsilyl)-4-phenyl-1-oxa-1,3-butadiene (20) react with Fe2(CO)9 to form highly stable crystalline tricarbonyliron(0) complexes (16 and (21). Complexes (16) and (21) both undergo acylation when reacted with methyl lithium under nitrogen to form γ-ketoacylsilanes [(18) and (22)], but only complex (21) reacts with methyl lithium under carbon monoxide to give the tricarbonyl(vinylketene)iron(0) complex (23).
Acylsilane chemistry. Synthesis of regio- and stereoisomerically defined enol silyl ethers using acylsilanes
Reich, Hans J.,Holtan, Ronald C.,Bolm, Carsten
, p. 5609 - 5617 (2007/10/02)
The preparation of enol silyl ethers using a carbonyl addition-Brook rearrangement-elimination sequence was studied. The key intermediate α-silyl-β-X-alkoxides could be prepared in several different ways, including the addition of organolithium or hydride reagents to α-X-acylsilanes (path a, using RM with R = alkyl, aryl, vinyl, alkynyl, silyl, stannyl, phosphinyl, and cyano), the addition of α-X-lithium reagents to acylsilanes (path b, X = phenylthio, phenylsulfonyl), or the addition of silyllithium reagents to α-X-ketones (path c, X = phenylthio, alkoxy). All of the reactions gave complete regiocontrol of silyl enol ether formation, and many gave excellent (>99%) stereocontrol as well. The selectivity of the carbonyl addition, silyl rearrangement, and elimination was studied. For path a, when the R group of RM was a poor carbanion stabilizing group the elimination of the intermediate α-silyl-β-X-alkoxides was stereospecific, and there was a large difference in rate between erythro and threo (erythro > threo). When R was a carbanion stabilizing group, such as aryl or alkynyl, the elimination process became nonstereospecific in some cases, and only small differences between threo and erythro were observed. Path b was especially effective with α-sulfonyl lithium reagents, and these reactions gave predominantly E enol silyl ethers (4/1 to 20/1). The addition of organolithium reagents to β-X-acylsilanes (the homologue of path a) was also briefly explored as a synthesis of siloxy-cyclopropanes.
