Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
作者:Amanda F. Silva、Marco A. S. Afonso、Rodrigo A. Cormanich、Igor D. Jurberg
DOI:10.1002/chem.201905812
日期:2020.5.4
visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemicalreaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates
Blue light-promoted N–H insertion of amides, isatins, sulfonamides and imides into aryldiazoacetates: Synthesis of unnatural α-aryl amino acid derivatives
作者:Celso Y. Okada、Caio Y. dos Santos、Igor D. Jurberg
DOI:10.1016/j.tet.2020.131316
日期:2020.12
A photochemical protocol using blue light allows the N–H insertion of amides, isatins, sulfonamides and imides into aryldiazoacetates to afford the corresponding α-amino esters. This method is experimentally simple, inexpensive and tolerates numerous functional groups, thus allowing the straightforward preparation of a variety of α-aryl amino acid derivatives in good yields.
Guide to enantioselective dirhodium(II)-catalyzed cyclopropanation with aryldiazoacetates
作者:Kathryn M. Chepiga、Changming Qin、Joshua S. Alford、Spandan Chennamadhavuni、Timothy M. Gregg、Jeremy P. Olson、Huw M.L. Davies
DOI:10.1016/j.tet.2013.04.075
日期:2013.7
Catalytic enantioselective methods for the generation of cyclopropanes have been of long standing pharmaceutical interest. Chiraldirhodium(II) catalysts prove to be an effective means for the generation of diverse cyclopropane libraries. Rh2(R-DOSP)4 is generally the most effective catalyst for asymmetric intermolecular cyclopropanation of methyl aryldiazoacetates with styrene. Rh2(S-PTAD)4 provides
用于生成环丙烷的催化对映选择性方法长期以来一直是制药业的兴趣所在。手性二铑 (II) 催化剂被证明是生成各种环丙烷库的有效手段。Rh 2 ( R -DOSP) 4通常是重氮乙酸甲酯与苯乙烯的不对称分子间环丙烷化反应最有效的催化剂。Rh 2 ( S -PTAD) 4提供高水平的邻位取代芳基重氮乙酸酯的对映体诱导。不太成熟的 Rh 2 ( R -BNP) 4对 Rh 2 ( R-DOSP) 4和 Rh 2 ( S -PTAD) 4在催化 3-甲氧基取代的重氮基乙酸芳基酯的高度对映选择性环丙烷化反应中。苯乙烯的取代对环丙烷化的不对称诱导仅具有中等影响。
Enantioselective Synthesis of α-Mercapto-β-amino Esters via Rh(II)/Chiral Phosphoric Acid-Cocatalyzed Three-Component Reaction of Diazo Compounds, Thiols, and Imines
作者:Guolan Xiao、Chaoqun Ma、Dong Xing、Wenhao Hu
DOI:10.1021/acs.orglett.6b03075
日期:2016.12.2
enantioselective method for the synthesis of α-mercapto-β-amino esters has been developed via a rhodium(II)/chiral phosphoric acid-cocatalyzed three-component reaction of diazo compounds, thiols, and imines. This transformation is proposed to proceed through enantioselective trapping of the sulfonium ylide intermediate generated in situ from the diazo compound and thiol by the phosphoric acid-activated
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
作者:Taoda Shi、Shenghan Teng、Alavala Gopi Krishna Reddy、Xin Guo、Yueteng Zhang、Kohlson T. Moore、Thomas Buckley、Damian J. Mason、Wei Wang、Eli Chapman、Wenhao Hu
DOI:10.1039/c9ob01903k
日期:——
report a bifunctional Ag catalyst promotedintramolecular capture of oxonium ylides with alkynes for the enantioselectivesynthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with