Tandem Claisen Rearrangement/6-<i>endo</i>Cyclization Approach to Allylated and Prenylated Chromones
作者:Bernd Schmidt、Martin Riemer、Uwe Schilde
DOI:10.1002/ejoc.201501151
日期:2015.12
o-acylphenols reacted upon microwave irradiation to form C-allylated or -prenylated chromone derivatives, depending on the substitution pattern of the arene and the allyl substituent. The reaction proceeds through a tandemClaisen rearrangement and 6-endo-trig or 6-endo-dig cyclization sequence. For prenyl ethers, the tandem sequence can be extended by a Cope rearrangement to furnish 6-prenylchromones.
Stereodivergent Alkyne Reduction by using Water as the Hydrogen Source
作者:Santhosh Rao、Kandikere Ramaiah Prabhu
DOI:10.1002/chem.201803147
日期:2018.9.18
homogeneous Pd‐catalyzed stereodivergent reduction of alkynes to Z and E alkenes by using H2O as the H2 source is presented. Mediated by a diboron reagent, the transfer hydrogenation has been accomplished to yield the desired geometrical isomer by rational ligand selection. The switchable stereoselectivity achieved using simple phosphine ligands is generally excellent. D2O has also been used as a D2 source
<i>tert</i>-Butyl Nitrite: Organic Redox Cocatalyst for Aerobic Aldehyde-Selective Wacker–Tsuji Oxidation
作者:Xiao-Shan Ning、Mei-Mei Wang、Chuan-Zhi Yao、Xian-Min Chen、Yan-Biao Kang
DOI:10.1021/acs.orglett.6b01165
日期:2016.6.3
An aldehyde-selective aerobic Wacker–Tsuji oxidation is developed. Using tert-butylnitrite as a simple organic redox cocatalyst instead of copper or silver salts, a variety of aldehydes were achieved as major products in up to 30/1 regioselectivity as well as good to high yields at room temperature.
Regioselective Wacker-Type Oxidation of Internal Olefins in <sup><i>t</i></sup>BuOH Using Oxygen as the Sole Oxidant and <sup><i>t</i></sup>BuONO as the Organic Redox Cocatalyst
作者:Qing Huang、Ya-Wei Li、Xiao-Shan Ning、Guo-Qing Jiang、Xiao-Wei Zhang、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.orglett.9b04503
日期:2020.2.7
A regioselective Wacker-Tsuji oxidation of internal olefins in tBuOH has been developed using oxygen as the terminal oxidant and tert-butyl nitrite as the simple organic redox cocatalyst without the involvement of hazardous cocatalysts or harsh reaction conditions. A series of internal olefins bearing various functional groups can be oxidized to the corresponding substituted ketones in generally good
Two possible routes for the synthesis of optically active olefinic compounds through cross-coupling reaction between allylic electrophiles and Grignard reagents catalyzed by nickel complexes containing chiral diphosphine ligands were investigated: i) the reaction of chiral racemic (or prochiral) allylic compounds with achiral Grignard reagents and ii) the reaction of chiral Grignard reagents with allyl