Enantioselective iodolactonization of allenoic acids
作者:Kenichi Murai、Nozomi Shimizu、Hiromichi Fujioka
DOI:10.1039/c4cc05414h
日期:——
An enantioselectiveiodolactonization reaction of allenoic acids has been developed using a trisimidazoline catalyst and I2. Our mechanistic study suggests the involvement of a pi-allyl cation intermediate in this reaction system.
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
作者:Taoda Shi、Shenghan Teng、Alavala Gopi Krishna Reddy、Xin Guo、Yueteng Zhang、Kohlson T. Moore、Thomas Buckley、Damian J. Mason、Wei Wang、Eli Chapman、Wenhao Hu
DOI:10.1039/c9ob01903k
日期:——
report a bifunctional Ag catalyst promotedintramolecular capture of oxonium ylides with alkynes for the enantioselectivesynthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with
A convenient zinc‐promoted [4+3] cycloaddition of a carbonyl ene–yne with simple dienes was first achieved. This reaction provided an efficient strategy to prepare various cyclohepta[b]furan rings by cascade cycloadditions. Additionally, a multicomponent reaction of dione, alkynal, and diene was also reported, which exhibited a novel strategy for selective creations of CO bonds and CC bonds.
首先实现了一种简单的锌促进的羰基烯-炔的锌促进的[4 + 3]环加成反应。该反应提供了通过级联环加成反应制备各种环庚[ b ]呋喃环的有效策略。此外,二酮,炔醛,和二烯的多组分反应也有报道,其显示了用于使C选择性创作的新策略 O键和C C键。
Relay catalysis: combined metal catalyzed oxidation and asymmetric iminium catalysis for the synthesis of Bi- and tricyclic chromenes
作者:Magnus Rueping、Jeremy Dufour、Modhu Sudan Maji
DOI:10.1039/c2cc00129b
日期:——
A catalytic asymmetric oxidative iminium-allenaminecascade allows the use of propargyl alcohols as stable substrates and yields valuable chiral bicyclic 4H-chromenes. A subsequent Michael addition-condensation domino reaction provides complex tricyclic 4H-chromenes in a highlyenantioselective fashion.
Copper-Catalyzed Cross-Nucleophile Coupling of β-Allenyl Silanes with Tertiary C–H Bonds: A Radical Approach to Branched 1,3-Dienes
作者:Qi-Chao Shan、Lu-Min Hu、Wei Qin、Xu-Hong Hu
DOI:10.1021/acs.orglett.1c02112
日期:2021.8.6
3-dienes throughoxidative coupling of two nucleophilic substrates, β-allenyl silanes, and hydrocarbons appending latent functionality by copper catalysis. Notably, C(sp3)–H dienylation proceeded in a regiospecific manner, even in the presence of competitive C–Hbonds that are capable of occurring hydrogen atom transfer process, such as those located at benzylic and other tertiary sites, or adjacent to an