Reverse Regioselectivity in the Palladium(II) Thiourea Catalyzed Intermolecular Pauson-Khand Reaction
作者:Na Wu、Lujiang Deng、Lianzhu Liu、Qi Liu、Chuangchuang Li、Zhen Yang
DOI:10.1002/asia.201200783
日期:2013.1
Which way? Palladium thiourea catalyzed Pauson–Khand reaction of norbornene with substituted alkynoates to afford selectively either α‐carboxylated adducts or β‐carboxylated adducts with the reverse regioselectivity has been demonstrated for the first time. Control of the regioselectivity in this transformation is governed by the addition of LiCl. A mechanistic interpretation to account for this observed
Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles
作者:Rajkumar Lalji Sahani、Rai-Shung Liu
DOI:10.1002/anie.201610665
日期:2017.1.19
new gold‐catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results in a remarkable alkyne cleavage of initial propiolates. Unsubstituted isoxazoles proceed through an N attack step to yield formal [2+2+1]/[4+2] annulation products. These two annulation products arise initially
Chemo-, Regio-, and Stereoselective Copper(II)-Catalyzed Boron Addition to Acetylenic Esters and Amides in Aqueous Media
作者:Amanda K. Nelson、Cheryl L. Peck、Sean M. Rafferty、Webster L. Santos
DOI:10.1021/acs.joc.6b00648
日期:2016.5.20
Aqueous conditions were developed for conducting an open-to-air, copper(II)-catalyzed addition of pinBBdan to alkynoates and alkynamides. The simple and mild β-borylation protocol proceeds in a remarkably chemo-, regio-, and stereoselective fashion to afford 1,8-diaminonaphthalene protected (Z)-β-boryl enoates and primary, secondary, and tertiary enamides in good to excellent yields. These reactions
Rh/bisphosphine−thiourea ligand (ZhaoPhos)‐catalyzed asymmetric hydrogenation of (Z)‐β‐substituted‐β‐boryl‐α,β‐unsaturatedesters was successfully developed, furnishing a variety of chiral β‐borylated carboxylic esters with high yields and excellent enantioselectivities (up to 99% yield and >99% ee). The gram‐scale asymmetric hydrogenation was performed efficiently in the presence of only 0.05 mol%
成功开发了Rh /双膦-硫脲配体(ZhaoPhos)催化的(Z)-β-取代的-β-硼基-α,β-不饱和酯的不对称加氢反应,提供了高收率的多种手性β-硼化羧酸酯优异的对映选择性(高达99%的收率和> 99%的ee)。在仅0.05 mol%(S / C = 2 000)催化剂负载的情况下,可以有效地进行克级不对称氢化反应,并具有完全转化率,99%的收率和99%的ee。此外,加氢产物很容易转化为其他通用的合成中间体,例如(S)-3-羟基-3-苯基丙酸甲酯和(S)-3-(呋喃-2-基)-3-苯基丙酸甲酯。