Regioselective Reductive Hydration of Alkynes To Form Branched or Linear Alcohols
摘要:
The regioselective reductive hydration of terminal alkynes using two complementary dual catalytic systems is described. Branched or linear alcohols are obtained in 75-96% yield with >= 25:1 regioselectivity from the same starting materials. The method is compatible with terminal, di-, and trisubstituted alkenes. This reductive hydration constitutes a strategic surrogate to alkene oxyfunctionalization and may be of utility in multistep settings.
Described herein is a visible‐light‐mediated atom‐transfer radical cyclization (ATRC) using 1,6‐enynes as substrates. The sulfonyl chlorides not only served as sulfonyl radical sources but also provided a chlorine atom to enable the formation of highly functionalized cyclic products. This visible‐light‐mediated photocatalytic method is a mild and practical strategy for synthesizing chloroalkyl‐substituted
The first enantioselective intramolecularC−Hinsertion and cyclopropanation reactions of donor‐ and donor/donor‐carbenes by a nondiazo approach are reported. The reactions were conducted in a one‐pot manner without slow addition and provided the desired dihydroindole, dihydrobenzofuran, tetrahydrofuran, and tetrahydropyrrole derivatives with up to 99 % ee and 100 % atom efficiency.
Atom Transfer Radical Addition to Alkynes and Enynes: A Versatile Gold/Photoredox Approach to Thio-Functionalized Vinylsulfones
作者:Haoyu Li、Zengrui Cheng、Chen-Ho Tung、Zhenghu Xu
DOI:10.1021/acscatal.8b02194
日期:2018.9.7
visible-light photoredoxcatalysis and gold catalysis has been developed, affording diverse trifluoromethylthio- and difluoromethylthio-functionalized vinylsulfones with high stereoselectivity in good yields. Thiosulfonylation reaction of enyne can also be realized for constructing functionalized carbo- and heterocyclesthrough a radical cascade cyclization process. These reactions proceed through a gold-assisted
Mechanism‐Based Approach to Reagent Selection for Oxidative Carbon−Hydrogen Bond Cleavage Reactions
作者:Jenna L. Miller、Lin Zhou、Peng Liu、Paul E. Floreancig
DOI:10.1002/chem.202103078
日期:2022.1.3
Selecting the optimal reagent for an oxidative C−H cleavage reaction requires mechanistic understanding of these processes. This manuscript describes an experimental approach to identify the role of substrate oxidation potential, cation stability, and steric factors on reaction rates and yields with common oxidants. The results are explained through computational transition state energetic and geometric
Synthesis of Cyclopropyl-Substituted Furans by Brønsted Acid Promoted Cascade Reactions
作者:J. Stephen Clark、Filippo Romiti、Kirsten F. Hogg、Malai Haniti S. A. Hamid、Sven C. Richter、Alistair Boyer、Joanna C. Redman、Louis J. Farrugia
DOI:10.1002/anie.201500625
日期:2015.5.4
Chloroacetic acidpromotes an efficient and diastereoselective intramolecular cascadereaction of electron‐deficient ynenones to deliver products featuring a 2,3,5‐trisubstituted furan bearing a fused cyclopropyl substituent at the 5‐position. Synthetically relevant polycyclic building blocks featuring rings of various sizes and heteroatoms have been synthesized in high yield using this mild acid‐catalyzed