of carbonyl compounds has been developed. When carbonyl compounds were allowed to react with trimethylsilyl phenylselenide and tributylstannyl hydride in the presence of a catalytic amount of AIBN as the radical initiator, hydrosilylation of the carbonyl compounds efficiently proceeded to give the corresponding silyl ethers in moderate to good yields. In the absence of carbonyl compounds, the triethylsilyl
Lanthanum Tricyanide-Catalyzed Acyl Silane−Ketone Benzoin Additions and Kinetic Resolution of Resultant α-Silyloxyketones
作者:James C. Tarr、Jeffrey S. Johnson
DOI:10.1021/jo100312w
日期:2010.5.21
We report the full account of our efforts on the lanthanum tricyanide-catalyzed acyl silane ketone benzoin reaction. The reaction exhibits a wide scope in both acyl silane (aryl, alkyl) and ketone (arylalkyl, alkyl-alkyl, aryl-aryl, alkenyl-alkyl, alkynyl-alkyl) coupling partners. The diastereoselectivity of the reaction has been examined in both cyclic and acyclic systems. Cyclohexanones give products arising from equatorial attack by the acyl silane. The diastereoselectivity of acyl silane addition to acyclic alpha-hydroxy ketones can be controlled by varying the protecting group to obtain either Felkin-Ahn or chelation control. The resultant alpha-silyloxyketone products can be resolved with selectivity factors from 10 to 15 by subjecting racemic ketone benzoin products to CBS reduction.
Teichmann,H.; Prey,V., Justus Liebigs Annalen der Chemie, 1970, vol. 732, p. 121 - 130
作者:Teichmann,H.、Prey,V.
DOI:——
日期:——
GRUENEWALD, H., ANGEW. CHEM., 1981, 93, N 9, 836-838
作者:GRUENEWALD, H.
DOI:——
日期:——
Chemoselective Activation of Trimethylsilyl Enol Ether Functionalities in the Presence of Silyl-Protected Alcohols by Trimethylsilyl-Nonaflyl Exchange
Trimethylsilyl enol ethers bearing trialkylsilyl-protected hydroxy groups were converted into synthetically valuable bifunctional alkenyl nonaflates under the action of nonafluorobutane-1-sulfonyl fluoride combined with potassium fluoride in the presence of catalytic amounts of dibenzo-18-crown-6. The methodology has been demonstrated for structurally diverse substrates possessing various trialkylsilyl-protected hydroxy groups which remained intact during the reaction course.