Chemoselective hydroperoxidation of alkenylarenes within thionin-supported zeolite Na-Y
摘要:
Photooxidation of several 1-aryl-2-methylpropenes within the thionin-supported zeolite Na-Y affords the ene type allylic hydroperoxides in a highly chemoselective manner. This is in contrast to their photooxygenation reaction in solution, where the e,le pathway is less favorable compared to the [4+2] or [2+2] pathways. Cation-pi interactions are likely to be responsible for this selectivity. (C) 2001 Published by Elsevier Science Ltd.
Control of Regioselectivity by the <i>l</i><i>one</i> Substituent through Steric and Electronic Effects in the Nitrosoarene Ene Reaction of Deuterium-Labeled Trisubstituted Alkenes
For the enereaction of 4-nitronitrosobenzene (ArNO) with a variety of primary and secondary lone alkyl-substituted substrates, the twix/twin regioselectivity is constant at about 85:15. In contrast, for the lone tert-butyl group and for lone aryl substituents, the twix regioisomer is obtained exclusively. These regioselectivities have been rationalized in terms of steric interactions and coordination
Electrophotocatalytic Acetoxyhydroxylation of Aryl Olefins
作者:He Huang、Tristan H. Lambert
DOI:10.1021/jacs.1c01967
日期:2021.5.19
conditions is described. The procedure uses a trisaminocyclopropenium (TAC) ion catalyst with visible light irradiation under a controlled electrochemical potential to convert aryl olefins to the corresponding glycol monoesters with high chemo- and diastereoselectivity. This reaction can be performed in batch or in flow, enabling multigram synthesis of the monoester products.
recent efforts, a catalytic and convenient strategy for the direct alkylation of unactivated allylic or benzylic sp3 C-H bonds remains a formidable challenge facing the synthesis community. We herein report an unprecedented allylic/benzylic alkylation using only an organo-photoredox catalyst, which enables coupling of a broad scope of alkenes/arenes and electron-deficient alkenes in an atom- and redox-economic
Catalytic Intermolecular C(sp<sup>3</sup>)–H Amination: Selective Functionalization of Tertiary C–H Bonds vs Activated Benzylic C–H Bonds
作者:Erwan Brunard、Vincent Boquet、Elsa Van Elslande、Tanguy Saget、Philippe Dauban
DOI:10.1021/jacs.1c03872
日期:2021.5.5
A catalytic intermolecular amination of nonactivated tertiary C(sp3)–H bonds (BDE of 96 kcal·mol–1) is reported for substrates displaying an activated benzylic site (BDE of 85 kcal·mol–1). The tertiary C(sp3)–H bond is selectively functionalized to afford α,α,α-trisubstituted amides in high yields. This unusual site-selectivity results from the synergistic combination of Rh2(S-tfpttl)4, a rhodium(II)
作者:Gino Occhialini、Vignesh Palani、Alison E. Wendlandt
DOI:10.1021/jacs.1c12043
日期:2022.1.12
The positional isomerization of C═C double bonds is a powerful strategy for the interconversion of alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less stable starting materials. Here, we report the discovery of a dual catalyst system that promotes contra-thermodynamic positional alkeneisomerization under photochemical irradiation, providing