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
Enantioselective Addition of Boronates to <i>o</i>-Quinone Methides Catalyzed by Chiral Biphenols
作者:Yi Luan、Scott E. Schaus
DOI:10.1021/ja309076g
日期:2012.12.12
Chiralbiphenols were found to catalyze the enantioselective asymmetric addition of aryl- or alkenylboronates to o-quinone methides. Substituted 2-styryl phenols were obtained in good yields (up to 95%) with high enantiomeric ratios (up to 98:2) in the presence of 10 mol % 3,3'-Br(2)-BINOL. A two-step synthesis of (S)-4-methoxydalbergione in good yield and selectivity was achieved.
Enantioselective Addition of Boronates to Chromene Acetals Catalyzed by a Chiral Brønsted Acid/Lewis Acid System
作者:Philip N. Moquist、Tomohiro Kodama、Scott E. Schaus
DOI:10.1002/anie.201003469
日期:2010.9.17
Chiral α,β‐dihydroxy carboxylic acids catalyze the enantioselectiveaddition of alkenyl and aryl boronates to chromene acetals. The optimal carboxylic acid is the easily available tartaric acid amide shown in the scheme. Spectroscopic and kinetic mechanistic studies demonstrate that an exchange process generates a reactive dioxoborolane intermediate leading to enantioselectiveaddition to the pyrylium
Organocatalytic Enantioselective Oxidative CH Alkenylation and Arylation of<i>N</i>-Carbamoyl Tetrahydropyridines and Tetrahydro-β-carbolines
作者:Xigong Liu、Zhilin Meng、Chengkun Li、Hongxiang Lou、Lei Liu
DOI:10.1002/anie.201500703
日期:2015.5.11
The first organocatalyticenantioselectiveCHalkenylation and arylation reactions of N‐carbamoyl tetrahydropyridines and tetrahydro‐β‐carbolines (THCs) are described. The metal‐free processes represent an efficient and straightforward approach to a variety of structurally and electronically diverse α‐substituted tetrahydropyridines and THCs in good yields with excellent regio‐ and enantioselectivities
Asymmetric Organocatalytic Homologation: Access to Diverse Chiral Trifluoromethyl Organoboron Species
作者:Ramasamy Jayarajan、Tautvydas Kireilis、Lars Eriksson、Kálmán J. Szabó
DOI:10.1002/chem.202202059
日期:2022.10.18
Highly enantioselective α-trifluoromethylated aliphatic, aromatic, and heterocyclic boronic acids and boronates were synthesized from simple feedstocks.