Catalytic Asymmetric [4+2]-Cycloaddition of Dienes with Aldehydes
作者:Luping Liu、Hyejin Kim、Youwei Xie、Christophe Farès、Philip S. J. Kaib、Richard Goddard、Benjamin List
DOI:10.1021/jacs.7b08357
日期:2017.10.4
Despite its significant potential, a general catalytic asymmetric [4+2]-cycloaddition of simple and electronically unbiased dienes with any type of aldehyde has long been unknown. Previously developed methodologies invariably require activated, electronically engineered substrates. We now provide a general solution to this problem. We show that highly acidic and confined imidodiphosphorimidates (IDPis)
Modular Monodentate Oxaphospholane Ligands: Utility in Highly Efficient and Enantioselective 1,4-Diboration of 1,3-Dienes
作者:Christopher H. Schuster、Bo Li、James P. Morken
DOI:10.1002/anie.201102404
日期:2011.8.16
Tune it up! Tunable, chiral, monodentateoxaphospholaneligands (termed OxaPhos) are highly effective in the Pt‐catalyzed title reaction, providing the 1,4‐addition products in enantiomer ratios approaching 99:1 (see scheme). In the presence of enantiomerically pure cis‐iBu‐OxaPhos, a catalyst loading of only 0.02 mol % [Pt(dba)3] was sufficient for effective reaction. pin=pinacolato, dba=dibenzylideneacetone
Synthesis of Tertiary Benzylic Nitriles via Nickel-Catalyzed Markovnikov Hydrocyanation of α-Substituted Styrenes
作者:Yidan Xing、Rongrong Yu、Xianjie Fang
DOI:10.1021/acs.orglett.9b04554
日期:2020.2.7
The Markovnikov hydrocyanation of α-substituted styrenes enables the synthesis of tertiary benzylic nitriles under nickel catalysis. The Lewis-acid-free transformation features an unprecedented functional groups tolerance, including the -OH and -NH2 groups. A broad range of tertiary benzylic nitriles were obtained in good to excellent yields. In addition, an asymmetric version of this reaction was
Olefination of carbonyl compounds with gem-dizincioalkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.