Structurally Diverse α-Substituted Benzopyran Synthesis through a Practical Metal-Free C(sp<sup>3</sup>)–H Functionalization
作者:Wenfang Chen、Zhiyu Xie、Hongbo Zheng、Hongxiang Lou、Lei Liu
DOI:10.1021/ol503004a
日期:2014.11.21
A trityl ion-mediated practical C–H functionalization of a variety of benzopyrans with a wide range of nucleophiles (organoboranes and C–H molecules) at ambient temperature has been disclosed. The metal-free reaction has an excellent functional group tolerance and high chemoselectivity and displays a broad scope with respect to both benzopyran and nucleophile partners, efficiently affording a collection
Visible-light induced enhancement in the multi-catalytic activity of sulfated carbon dots for aerobic carbon–carbon bond formation
作者:Daisy Sarma、Biju Majumdar、Tridib K. Sarma
DOI:10.1039/c9gc02658d
日期:——
ketones, arenes and 1,3-dicarbonyl compounds that showed high efficiency and selectivity under visible-light irradiation. The sulphated carbon dots demonstrate dual catalytic properties, wherein they induced the rapid photooxidation of xanthenes in the presence of molecular oxygen to form a hydroperoxy intermediate followed by coupling of nucleophiles catalysed by the acidic surface functional groups.
A manganese dioxide (MnO2)-methanesulfonic acid (CH3SO3H) oxidation system has been developed to efficiently promote direct coupling of benzylic ethers and carbamates with simple ketones via oxidative C-H bond activation. The alkylation proceeds smoothly under air atmosphere to afford the corresponding products in good to excellent yields (53-87%). The employment of the combination of MnO2 and CH3SO3H is attractive on the basis of economical and environmental issues.
Copper(II) catalyzed cross-dehydrogenative coupling of cyclic benzylic ethers with simple carbonyl compounds by Na2S2O8
Copper(II) catalyzed cross-dehydrogenative coupling of cyclic benzylic ethers with a variety of simple carbonyl compounds mediated by Na2S2O8 is developed. The scope of carbonyl components is broad, including simple aldehydes as well as ketones. The use of Na2S2O8 as the oxidant for the CDC reaction is attractive based on economical and environmental factors.
开发了铜(II)催化的环状苄醚与各种由Na 2 S 2 O 8介导的简单羰基化合物的交叉脱氢偶联。羰基成分的范围很广,包括简单的醛以及酮。基于经济和环境因素,使用Na 2 S 2 O 8作为CDC反应的氧化剂是有吸引力的。