Staring from readily available polysubstituted allylic chlorides, a range of polysubstituted allyliczinc chlorides were obtained using a LiCl-mediated zinc dust insertion in 55−84% yield. A highly diastereoselective synthesis of homoallylic alcohols bearing up to two adjacent quaternary centers was achieved using these polysubstituted allyliczinc reagents.
Tandem Palladium and Isothiourea Relay Catalysis: Enantioselective Synthesis of α-Amino Acid Derivatives via Allylic Amination and [2,3]-Sigmatropic Rearrangement
作者:Stéphanie S. M. Spoehrle、Thomas H. West、James E. Taylor、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1021/jacs.7b05619
日期:2017.8.30
has been developed for the enantioselective synthesis of α-aminoacid derivatives containing two stereogenic centers from readily accessible N,N-disubstituted glycine aryl esters and allylic phosphates. The optimized process uses a bench-stable succinimide-based Pd precatalyst (FurCat) to promote Pd-catalyzed allylic ammonium salt generation from the allylic phosphate and the glycine aryl ester. Subsequent
Diastereoselective Synthesis of Homoallylic Alcohols with Adjacent Tertiary and Quaternary Centers by Using Functionalized Allylic Aluminum Reagents
作者:Zhihua Peng、Tobias D. Blümke、Peter Mayer、Paul Knochel
DOI:10.1002/anie.201003813
日期:2010.11.2
Sensitive functional groups, including ester and cyano groups, can be present in allylicaluminumreagents prepared by aluminum insertion in the presence of InCl3. These aluminum organometallic compounds undergo addition reactions to various functionalized aldehydes or ketones with remarkable diastereoselectivities allowing the construction of two adjacentquaternary and tertiarycenters (see scheme)
Uniting C1-Ammonium Enolates and Transition Metal Electrophiles via Cooperative Catalysis: The Direct Asymmetric α-Allylation of Aryl Acetic Acid Esters
作者:Kevin J. Schwarz、Jessica L. Amos、J. Cullen Klein、Dung T. Do、Thomas N. Snaddon
DOI:10.1021/jacs.6b01694
日期:2016.4.27
constitutes a significant challenge in the area of asymmetric catalysis, particularly where the configurational integrity of the products is problematic. Through the unprecedented merger of two independent, yet complementary, catalysis events it has been possible to facilitate the direct asymmetric α-allylation of readily available aryl aceticacid esters. Since enantioselection is determined by the nucleophile
Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts
作者:Guojiao Wu、Shuai Xu、Yifan Deng、Chaoqiang Wu、Xia Zhao、Wenzhi Ji、Yan Zhang、Jianbo Wang
DOI:10.1016/j.tet.2016.10.031
日期:2016.12
We report herein a transition-metal-free coupling reaction of arylboronic acids with benzyl halides and mesylates for the construction of C(sp2)C(sp3) bonds. A unique feature of this coupling reaction is the formation regioisomers in some cases. Mechanistic studies suggest that this reaction may proceed via an unprecedented Friedel–Crafts-type reactionpathway under base conditions with the assistance