Enantioselective dirhodium(II)-catalyzed cyclopropanations with trimethylsilylethyl and trichloroethyl aryldiazoacetates
作者:Solymar Negretti、Carolyn M. Cohen、Jane J. Chang、David M. Guptill、Huw M.L. Davies
DOI:10.1016/j.tet.2015.05.045
日期:2015.9
readily prepared by rhodium-catalyzedcyclopropanation of alkenes with aryldiazoacetates and styryldiazoaceates, in which the ester functionality is either trimethylsilylethyl (TMSE) or trichloroethyl (TCE). By having labile protecting groups on the ester, chiral triarylcyclopropane carboxylate ligands were conveniently prepared. The asymmetric induction during cyclopropanation is dependent on the
Rhodium(II)-Catalyzed Stereoselective Synthesis of Allylsilanes
作者:David M. Guptill、Carolyn M. Cohen、Huw M. L. Davies
DOI:10.1021/ol4028978
日期:2013.12.20
The rhodium-catalyzed decomposition of 2-(triisopropylsilyl)ethyl aryl- and vinyldiazoacetates results in the stereoselectiveformation of Z-allylsilanes. The transformation is considered to proceed by silyl-directed intramolecular C–H functionalization to form a β-lactone intermediate followed by a silyl-activated extrusion of carbon dioxide.
Low Pressure Carbonylation of Benzyl Carbonates and Carbamates for Applications in <sup>13</sup>C Isotope Labeling and Catalytic CO<sub>2</sub> Reduction
作者:Craig S. Day、Stephanie J. Ton、Clemens Kaussler、Daniel Vrønning Hoffmann、Troels Skrydstrup
DOI:10.1002/anie.202308238
日期:2023.8.28
Herein, an oxygen atom deletion strategy via sequential Pd-catalyzed decarboxylative carbonylation of carbonates and carbamates to afford esters and amides is reported. Operating under lowpressures (near stoichiometric or substoichiometric), either 13C labeled products are accessed or a proof-of-concept that CO2 formed upon decarboxylation can be reduced in situ and reincorporated as CO is shown.
在此,报道了通过碳酸酯和氨基甲酸酯的连续 Pd 催化脱羧羰基化以提供酯和酰胺的氧原子删除策略。在低压(接近化学计量或亚化学计量)下操作,可以获取13 C 标记的产品,也可以证明脱羧时形成的 CO 2可以原位还原并重新结合为 CO。
Dioxane promoted photochemical O-alkylation of 1,3-dicarbonyl compounds beyond carbene insertion into C–H and C–C bonds
作者:Xinlong Zhou、Jingjing Jiang、Min Zhang、Qingqing Wu、Keyong Zhu、Dongjie Shi、Sensen Hou、Jingjing Zhao、Pan Li
DOI:10.1039/d4cc00778f
日期:——
A photochemical synthesis of enol ethers and furan-3(2H)-ones from 1,3-dicarbonylcompounds and aryl diazoacetates has been developed. Significantly, 1,4-dioxane promoted O-alkylation of various 1,3-dicarbonylcompounds beyond previous carbene insertion into C–H and C–C bonds has been disclosed.
multicomponent reaction of vinyl sulfoxoniumylide, thiol, and diazo ester to generate tertiary sulfide is described. The present diastereoselective gem-difunctionalization of the diazo ester can be achieved under mild conditions, as it does not require any additives, catalysts, or transition metals and is tolerant of air and moisture. Due to more nucleophilicity, vinyl sulfoxoniumylide undergoes S–H insertion