Z- and E-selective Horner–Wadsworth–Emmons reactions
摘要:
In the present work, we determined and evaluated the stereochemical outcome of the Horner-Wadsworth-Emmons (HWE) reaction of 2-oxoalkylphosphonates with different ester functions (bis(2,2,2-trifluoroethyl), 2,2,2-trifluoroethyl methyl, dimethyl) and side chains (aliphatic, aromatic) with three different aldehydes (benzaldehyde, THP- and PPB-protected Corey aldehydes) under two reaction conditions. The trans protocol is generally used in the E-selective HWE reactions, while cis protocol promotes the Z-selectivity.[GRAPHICS].
Triazole-Gold-Promoted, Effective Synthesis of Enones from Propargylic Esters and Alcohols: A Catalyst Offering Chemoselectivity, Acidity and Ligand Economy
作者:Dawei Wang、Yanwei Zhang、Alexandria Harris、Lekh Nath S. Gautam、Yunfeng Chen、Xiaodong Shi
DOI:10.1002/adsc.201100314
日期:2011.10
(TA-Au) were revealed as the effectivecatalysts in promoting propargylicester rearrangement and sequential allene hydration, giving the enones with excellent yields (up to 97% yields, 0.2% loading). The catalysts could also catalyze the more challenging Meyer–Schuster rearrangement (0.5% loading, up to 98% yields). The reported reaction confirmed TA-Au as a chemoselectivecatalyst in promoting alkyne activation
Rearrangement of Allylic and Propargylic Alcohols Catalyzed by the Combined Use of tetrabutylammonium perrhenate (VII) and p-toluenesulfonic acid
作者:Koichi Narasaka、Hiroyuki Kusama、Yujiro Hayashi
DOI:10.1016/s0040-4020(01)88874-8
日期:1992.1
Allylic rearrangement and/or dehydration reaction of allylic alcohols proceeds smoothly by the use of catalytic amounts of tetrabutylammonium perrhenate and p-toluenesulfonic acid hydrate. Treatment of propargylic alcohols with the catalysts at room temperature affords the rearranged products, α,β-unsaturated carbonyl compounds, while, β,γ-unsaturated ketones are obtained as main products by the reaction
Contemporaneous Dual Catalysis by Coupling Highly Transient Nucleophilic and Electrophilic Intermediates Generated in Situ
作者:Barry M. Trost、Xinjun Luan
DOI:10.1021/ja110501v
日期:2011.2.16
contemporaneous dualcatalysis, that selectively couples two highly reactive catalytic intermediates while overcoming competing trapping by stoichiometric reactive species also present in the reaction. The reaction proceeds via the convergence of a vanadium-catalyzed propargylic rearrangement and a palladium-catalyzedallylicalkylation. It generates a variety of α-allylated α,β-unsaturatedketones, which are
Triazole acetyl gold(III) catalyzed Meyer–Schuster rearrangement of propargyl alcohols
作者:Yongchun Yang、Yanan Shen、Xiaoli Wang、Yao Zhang、Dawei Wang、Xiaodong Shi
DOI:10.1016/j.tetlet.2016.04.043
日期:2016.5
A new type triazole acetyl gold(III) was prepared and found to be an effective catalyst in Meyer–Schusterrearrangement of propargyl alcohols. The reactions proceeded well under much milder conditions to afford enones bearing a wide range of functional groups, thereby opening a new avenue for gold(III) catalysis. In addition, TriaAuCl2 catalyst was also effective on promotion of a-haloenones synthesis
The reactions of Z-rich unsaturated Weinreb amides with organolithium and organocerium reagents were examined. Taking in consideration both the extent of geometry retention and cleanness of the reaction, organocerium reagents were more effective for the conversion to Z-α,β-unsaturated ketones.
研究了富含 Z 的不饱和 Weinreb 酰胺与有机锂和有机铈试剂的反应。考虑到几何形状的保留程度和反应的清洁度,有机铈试剂在转化为 Z-α,β-不饱和酮方面更为有效。