The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed
Cobalt-Catalyzed Cross-Coupling of α-Bromo Amides with Grignard Reagents
作者:E. Barde、A. Guérinot、J. Cossy
DOI:10.1021/acs.orglett.7b02848
日期:2017.11.17
A cobalt-catalyzedcross-coupling between α-bromo amides and Grignardreagents is disclosed. The reaction is general and allows access to a large variety of α-aryl and β,γ-unsaturated amides. Some mechanistic investigations have been undertaken to determine the nature of the intermediate species.
O‐to‐S Substitution Enables Dovetailing Conflicting Cyclizability, Polymerizability, and Recyclability: Dithiolactone vs. Dilactone
作者:Yanchao Wang、Maosheng Li、Jinlong Chen、Youhua Tao、Xianhong Wang
DOI:10.1002/anie.202109767
日期:2021.10.4
chemically recyclable polymers represents a greener alternative to landfill and incineration and offers a closed-loop strategy toward a circular materials economy. However, the synthesis of chemically recyclable polymers is still plagued with certain fundamental limitations, including trade-offs between the monomer's cyclizability and polymerizability, as well as between polymer's depolymerizability and
Highly Stereoselective Synthesis of α-Alkyl-α-Hydroxycarboxylic Acid Derivatives Catalyzed by a Dinuclear Zinc Complex
作者:Barry M. Trost、Keiichi Hirano
DOI:10.1002/anie.201201116
日期:2012.6.25
dinuclear zinc–ProPhenol catalyst enables highly enantioselective nitro‐Michael reactions with oxazol‐4(5H)‐ones as nucleophilic substrates (see scheme, Nap=2‐naphthyl). This work highlights the utility of the ProPhenol family of ligands. The modular nature of these ligands proved crucial in the optimization of reaction conditions to achieve excellent stereoselectivities.
Synthesis of Highly Enantioenriched 3,4-Dihydroquinolin-2-ones by 6-<i>Exo-trig</i> Radical Cyclizations of Axially Chiral α-Halo-<i>ortho</i>-alkenyl Anilides
作者:David B. Guthrie、Steven J. Geib、Dennis P. Curran
DOI:10.1021/ja9066282
日期:2009.10.28
Radicalcyclizations (Bu(3)SnH, Et(3)B/air, rt) of racemic alpha-halo-ortho-alkenyl anilides provide 3,4-dihydroquinolin-2-ones in high yield. Cyclizations of enantioenriched precursors occur in similarly high yields and with transfer of axialchirality to the new stereocenter of the products with exceptionally high fidelity (often >95%). Single and tandem cyclizations of alpha-halo-ortho-alkenyl anilides