The coupling of α,β-unsaturated carbonyl compounds with aldehydes (the Baylis-Hillman reaction) was accelerated in the presence of a catalytic amount of 1,4-diazabicyclo[2,2,2]octane (DABCO) and lithium perchlorate in ether. A preliminary kinetic study revealed that the relative rate of the reaction using LiClO4 in ether was 8.0×102 times faster than that of the reaction without LiClO4.
An Improved Protocol for the Morita‐Baylis‐Hillman Reaction Allows Unprecedented Broad Synthetic Scope
作者:Nilton S. Camilo、Hugo Santos、Lucas A. Zeoly、Fábio S. Fernandes、Manoel T. Rodrigues、Thiago S. Silva、Samia R. Lima、José Cláudio Serafim、Aline S. B. de Oliveira、Arthur G. Carpanez、Giovanni W. Amarante、Fernando Coelho
DOI:10.1002/ejoc.202101448
日期:2022.3.7
By the combination of DABCO and aceticacid under solvent-free conditions, the Morita-Baylis-Hillman reaction rate of both activated and non-activated aldehydes increased significantly. The disclosed procedure is operationally simple and is compatible with a wide array of both nucleophilic and electrophilic reaction partners.
A short approach toward new acrolein‐type derivatives, functionalized in position 2 is described. It involves, as the key step, a smooth transformation of acylsilanes into aldehydes by irradiation in water‐organic solvent mixtures. The functionalized enals obtained by this newroute appear as versatile building blocks for the preparation of natural products and/or bioactive compounds.
[GRAPHICS]Treatment of acrolein with a TiCL4-n-Bu(4)Nl mixed reagent in the presence of 2 equiv of aldehydes provided 4-hydroxy-1,3-dioxane derivatives in good yields with high stereoselectivities. The use of vinyl ketones instead of acrolein afforded aldo-type adducts with high syn selectivities.