Condensation reactions of halogermanes and halosilanes with cyclohexene oxide
作者:A.A. Lavigne、J. Tancrede、R.M. Pike、C.T. Tabit
DOI:10.1016/s0022-328x(00)86323-8
日期:1968.11
Condensation products of several halogermanes and halosilanes with cyclohexene oxide have been identified and characterized. The opening of the oxide linkage of cyclohexene oxide has been investigated through hydrolysis of the intermediate products (cis/transcyclohexene halohydrin isomers) produced in these reactions. It is proposed that the subject condensation reactions proceed via a pentacovalent
Scope and limitations of one-pot multistep reactions with heterogeneous catalysts: The case of alkene epoxidation coupled to epoxide ring-opening
作者:José M. Fraile、Nuria García、Clara I. Herrerías、José A. Mayoral
DOI:10.1016/j.cattod.2011.03.067
日期:2011.9
The combination of two reactions in one-pot multistep system requires the compatibility not only between the catalysts of both reactions, but also between all the reaction components and conditions. In the case of the coupling of alkene epoxidation and epoxide ring opening, it has been possible to synthesize cyanohydrin and azidohydrin derivatives through a simple process that involves a one-pot multistep process by using a mixture of two heterogeneous catalysts, a silica-grafted Ti catalyst and ytterbium chloride, whose efficiency depends on the reactivity of the starting alkene. In addition, in some cases the mixture of catalysts can be recovered and reused in several one-pot multistep cycles. However, this system is not possible with electron- deficient alkenes, as the basic catalyst required for epoxidation has shown to be incompatible with the ring-opening process. (C) 2011 Elsevier B.V. All rights reserved.
Asymmetric Ring Opening of Meso Epoxides with TMSCN Catalyzed by (pybox)lanthanide Complexes
作者:Scott E. Schaus、Eric N. Jacobsen
DOI:10.1021/ol005721h
日期:2000.4.1
[GRAPHICS]The asymmetric ring opening of meso epoxides with TMSCN is catalyzed by (pybox)YbCl3 complexes, yielding the beta-trimethylsilyloxy nitrile ring-opened products with good enantioselectivities (83-92% ee). The reaction exhibits a second-order kinetic dependence on catalyst concentration and a first-order dependence on epoxide concentration, consistent with a bimetallic pathway involving simulataneous activation of epoxide and cyanide.
Iqbal, Javed; Khan, M. Amin; Ahmad, Saeed, Synthetic Communications, 1989, vol. 19, # 3and4, p. 641 - 644