Further Improvement on Sulfonamide-Based Ligand for Catalytic Asymmetric 2-Haloallylation and Allylation
摘要:
The sulfonamide-based ligand B was found to exhibit an outstanding crystallinity and perform well as a ligand for Cr-mediated catalytic asymmetric 2-haloallylation and allylation. The new ligand has an appealing advantage over the first generation ligand; its high crystallinity allows effective recovery of the ligand from a reaction in a pure form.
A highly selective C-H amination reaction under iron catalysis has been developed. This novel system, which employs an inexpensive, nontoxic [Fe(III)Pc] catalyst (typically used as an industrial ink additive), displays a strong preference for allylic C-H amination over aziridination and all other C-H bond types (i.e., allylic > benzylic > ethereal > 3° > 2° ≫ 1°). Moreover, in polyolefinic substrates
Chiral sulfoxides as activators of allyl trichlorosilanes in the stereoselective allylation of aldehydes
作者:Vincenzo De Sio、Antonio Massa、Arrigo Scettri
DOI:10.1039/c002988b
日期:——
Chiral aryl methyl sulfoxides proved to be efficient activators in the asymmetric allylation of aldehydes with allyl trichlorosilanes. High enantioselectivity was found in the case of electron-poor aldehydes. The high levels of diastereoselectivity and the detection of nonlinear effects have allowed the elucidation of some mechanistic aspects of the reaction.
The stability of a photocatalyst under irradiation is important in photoredox applications. In this work, we investigated the stability of a thermallyactivateddelayed fluorescence (TADF) photocatalyst 3DPAFIPN [2,4,6-tris(diphenylamino)-5-fluoroisophthalonitrile]}, recently employed in photoredox-mediated processes, discovering that in the absence of quenchers the chromophore is unstable and is
Further Improvement on Sulfonamide-Based Ligand for Catalytic Asymmetric 2-Haloallylation and Allylation
作者:Zhiyu Zhang、Jian Huang、Bin Ma、Yoshito Kishi
DOI:10.1021/ol801093p
日期:2008.7.17
The sulfonamide-based ligand B was found to exhibit an outstanding crystallinity and perform well as a ligand for Cr-mediated catalytic asymmetric 2-haloallylation and allylation. The new ligand has an appealing advantage over the first generation ligand; its high crystallinity allows effective recovery of the ligand from a reaction in a pure form.
Determination of absolute configurations of β- or γ-methyl substituted secondary alcohols by NMR spectroscopy
作者:Haruko Takahashi、Makoto Iwashima、Kazuo Iguchi
DOI:10.1016/s0040-4039(98)02344-2
日期:1999.1
determining the absolute configurations of acyclic β- or γ-methyl substituted secondary alcohols using their 2NMA esters. The 1H-NMR spectra of (R)- and (S)-2NMA esters of model compounds were measured, and Δδ values (δR-ester - δS-ester) for the corresponding protons were compared between syn and anti compounds. Threshold values important for judging the relative stereochemistry of the two chiral centers