Synthesis of <i>trans</i>-stilbenes <i>via</i> phosphine-catalyzed coupling reactions of benzylic halides
作者:Sheng Zhang、Zhilong Xie、Zhanqiang Ye、Mingyang Zhang、Dongdeng Li、Masahiko Yamaguchi、Ming Bao
DOI:10.1039/d2ob01237e
日期:——
are also generated from the reactions of benzyl chlorides with phosphoniumsalts. Several P-based key intermediates have been detected by NMR and HRMS analyses, which shed light on the postulated catalytic cycle. In the presence of different bases, the transformations involve two different pathways, in which phenylcarbene and phosphonium alkoxide are considered as key intermediates, respectively. The
描述了一种高效实用的膦催化氯化苄的均偶联反应。在 CsF/B(OMe) 3和 NaH 作为碱的存在下,反应顺利进行,分别提供反式-二苯乙烯产量高,范围广。苄基氯与鏻盐的反应也产生不对称二苯乙烯。通过 NMR 和 HRMS 分析检测到几种 P 基关键中间体,这揭示了假定的催化循环。在不同碱基存在下,转化涉及两种不同的途径,其中苯卡宾和醇鏻分别被认为是关键中间体。这两种途径在合成上互补,但在机制上不同。合成效用,包括克级反应和直接获得 π 共轭分子,也已得到证明。
Construction of Alkylidene Fluorene Scaffolds Using Pd-Catalyzed Direct Arene/Alkene Coupling Strategy
作者:Hidenori Matsuyama、Xuan Zhang、Masahiro Terada、Tienan Jin
DOI:10.1021/acs.orglett.2c04307
日期:2023.2.10
alkylidene fluorenes and their heteroarene derivatives has been developed successfully by means of a Pd(II)-catalyzed direct C–H/C–H coupling of o-alkenyl biaryls. Use of the Pd(OAc)2 catalyst under aerobic oxidation conditions gives rise to the corresponding alkylidene fluorenes having various functional groups and diversely fused polycyclic systems. The resulting products can serve as versatile synthetic
Stereoselective Synthesis of <i>trans</i>-Stilbenes through Silver-Catalyzed Self-Coupling of <i>N</i>-Triftosylhydrazones: An Experimental and Theoretical Study
作者:Qingmin Song、Yue Zhao、Shaopeng Liu、Yong Wu、Zhaohong Liu
DOI:10.1021/acs.orglett.3c01040
日期:2023.5.19
efficiency with excellent stereoselectivity, broad substrate scope, and good functional group tolerance. A plausible mechanism involving nucleophilic attack of in situ generated sulfonium ylides on silver carbene was proposed on the basis of experimental results and DFT calculations, which further indicates that π–π stacking interactions play a dominant role in stereoselectivity control.
Catalytic Enantioselective and Catalyst-Controlled Diastereofacial-Selective Additions of Allyl- and Crotylboronates to Aldehydes Using Chiral Brønsted Acids
作者:Vivek Rauniyar、Dennis G. Hall
DOI:10.1002/anie.200504432
日期:2006.4.3
sym-1,2-Diarylethylenes from .alpha.-lithiated benzylic sulfones. Catalysis by elemental tellurium