117775-79-8Relevant academic research and scientific papers
METAL SALT-PROMOTED ALDOL REACTION OF SILYL ENOL ETHERS WITH ALDEHYDES
Chini, Marco,Crotti, Paolo,Gardelli, Cristina,Minutolo, Filippo,Pineschi, Mauro
, p. 673 - 676 (2007/10/02)
Simple metal salts such as lithium perchlorate and zinc triflate effectively promote aldol condensation between silyl enol ethers and aldehydes or acetals in non-protic solvents to yield the O-protected aldols in good yields. A slight preference for the syn aldol is observed when a prochiral silyl enol ether reacts with benzaldehyde, a complete syn stereoselectivity being obtained only in the case of the hindered silyl enol ether 14. The method appears to be simple and competitive with other ones previously described.
Synthesis of η1 Oxygen-Bound Rhodium Enolates. Applications to Catalytic Aldol Chemistry
Slough, Greg A.,Bergman, Robert G.,Heathcock, Clayton H.
, p. 938 - 949 (2007/10/02)
Oxygen-bound rhodium enolate complexes are prepared by metathesis of carbonylbis(phosphine)rhodium(I) halides and potassium enolates, 3-6.Rhodium enolates of acetophenone (7), propiophenone (9), ethyl mesityl ketone (10), and ethyl tert-butyl ketone (11) were prepared and fully characterized.Complex 11 condenses with benzaldehyde under a variety of conditions to produce isolable rhodium aldolate complex 12.Cleavage of 12 with trimethylsilyl chloride yields aldol silyl ether and rhodium chloride.Similar treatment of 12 with an enol silane affords the aldol silylether and a rhodium enolate.A catalytic aldol reaction involving enol silanes, silylketene acetals, and benzaldehyde under rhodium catalysis is presented.Deuterium, phosphorus, and carbon NMR were used to demonstrate the intermediacy of rhodium enolates and aldolates in the aldol process and to elucidate the gross mechanistic features of the catalytic cycle.
