Acyclic stereoselection. 9. Stereochemistry of the addition of lithium enolates to .alpha.-alkoxy aldehydes
作者:Clayton H. Heathcock、Steven D. Young、James P. Hagen、Michael C. Pirrung、Charles T. White、Don VanDerveer
DOI:10.1021/jo01307a023
日期:1980.9
Regio- and Stereochemistry on the Electrophilic Trapping of Allylic Samariums Generated by Reductive Cleavage of Allylic Ethers with (C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>Sm(thf)<sub><i>n</i></sub>
The C-O bond of allylic benzyl ethers was selectively cleaved with Cp-2*Sm(thf)(n) to give allylic samarium complexes in good yields. Facility of their bond fission has been found to be comparable to that of the corresponding propargylic ethers intermolecularly, but lower intramolecularly. Regio- and stereochemistry on the electrophilic trapping of the allylic complexes thus generated remarkably depended on the nature of the electrophiles. They reacted with carbonyl compounds exclusively from the most substituted terminus of the allylic moieties to yield blanched homoallylic alcohols with anti diasteroselectivity. On the other hand, trapping with silyl chlorides produced linear allylic silanes. Here, a plausible mechanism to account for the difference is proposed.
Bateson, John H.; Quinn, Alison M.; Smale, Terence C., Journal of the Chemical Society. Perkin transactions I, 1985, p. 2219 - 2234
作者:Bateson, John H.、Quinn, Alison M.、Smale, Terence C.、Southgate, Robert
DOI:——
日期:——
Silylene oxonium ylides: di-tert-butylsilylene insertion into C–O bonds
作者:Laura E. Bourque、Pamela A. Haile、Janice M.N. Loy、K.A. Woerpel
DOI:10.1016/j.tet.2009.04.016
日期:2009.7
Allylic ethers undergo insertions of silylenes into C-O bonds to form allylic silanes. Silylene insertion into C-O acetal bonds was also observed. Formation of silylene ylide intermediates led to [ 1,2]-Stevens rearrangement products as well as [2,3]-sigmatropic products depending upon the steric environment of the starting allylic ether. (C) 2009 Elsevier Ltd. All rights reserved.