Herein, the synthesis of (Z)-α,β-unsaturated nitriles by a sequential hydroformylation/Knoevenagel reaction has been first developed. A variety of crude α-olefins from Fischer–Tropsch synthesis, internal and special olefins, as well as alkynes could be transformed into value-added alkenyl nitriles (39 examples) up to 90% yield. Remarkably, compared with commonly used tedious multistep reactions, the
在此,首次开发了通过顺序加氢甲酰化/Knoevenagel 反应合成 ( Z )-α,β-不饱和腈。来自费-托合成的各种粗α-烯烃、内烯烃和特殊烯烃以及炔烃可以转化为增值的烯基腈(39 个例子),产率高达 90%。值得注意的是,与常用的繁琐的多步反应相比,一锅法的特点是原料便宜且容易获得,具有优异的化学选择性、区域选择性和立体选择性,反应条件非常温和,易于放大生产。
Direct Synthesis of α,β-Unsaturated Nitriles Catalyzed by Nonionic Superbases
作者:Bosco A. D'Sa、Philip Kisanga、John G. Verkade
DOI:10.1021/jo972343u
日期:1998.6.1
We report herein the use of 3-30 mol % of a new class of tricyclic strong nonionic Lewis bases P(MeNCH2CH2)(3)N and P(HNCH2CH2)(i-PrNCH2CH2)(2)N for the direct catalytic synthesis of a variety of functionalized alpha,beta-unsaturated nitriles in high yields from aldehydes and acetonitrile or benzyl cyanide at 40-50 degrees C. Evidence for a novel mechanistic pathway proposed for this reaction in a polar protic solvent such as methanol, and a nonpolar aprotic solvent such as benzene is also presented. Under these conditions, primary and secondary aliphatic aldehydes do not condense satisfactorily with acetonitrile to give the alpha,beta-unsaturated nitrile, and ketones do not condense with either benzyl cyanide or acetonitrile.
Reconstructed Hydrotalcite as a Highly Active Heterogeneous Base Catalyst for Carbon−Carbon Bond Formations in the Presence of Water
reaction of carbonyl compounds is efficiently catalyzed by reconstructed hydrotalcites, obtained by treating the Mg−Al mixed oxide with water, as solid base catalysts in the presence of water. The catalysis of the reconstructed hydrotalcites is attributable to the surface base sites, created during the organization of the layered structure, with uniformly distributed strength. Furthermore, the reconstructed