Cyanomethyl anion transfer reagents for diastereoselective Corey–Chaykovsky cyclopropanation reactions
作者:Renè Hommelsheim、Katharina J. Hock、Christian Schumacher、Mohanad A. Hussein、Thanh V. Nguyen、Rene M. Koenigs
DOI:10.1039/c8cc05602a
日期:——
A readily available and bench-stable cyanomethyl sulfonium salt was used in highly diastereoselective Corey–Chaykovsky cyclopropanationreactions of electron-poor olefins. This efficient method provides a rapid route to access densely functionalized cyclopropyl nitriles.
Highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins catalyzed by a chiral glucose-based bifunctional secondary amine-thiourea catalyst
A novel bifunctional thiourea bearing a saccharide-scaffold and a secondary amino group was synthesized, and was proven to be an effective organocatalyst for the asymmetric Michael reaction of cyclohexanone to both aryl and alkyl nitroolefins. The corresponding adducts were obtained with excellent diastereo- (up to >99/1 dr) and enantioselectivities (up to 97% ee).
Reducing-Agent-Free Convergent Synthesis of Hydroxyimino-Decorated Tetracyclic Fused Cinnolines via Rh<sup>III</sup>-Catalyzed Annulation Using Nitroolefins
作者:Pidiyara Karishma、Chikkagundagal K. Mahesha、Sanjay K. Mandal、Rajeev Sakhuja
DOI:10.1021/acs.joc.0c02729
日期:2021.2.5
A mild Rh-catalyzed method was developed for the synthesis of hydroxyimino functionalized indazolo[1,2-a]cinnolines and phthalazino[2,3-a]cinnolines by reductive [4 + 2] annulation between 1-arylindazolones and 2-aryl-2,3-dihydrophthalazine-1,4-diones with varied nitroolefins. The targeted oxime decorated tetracyclic fused cinnolines were synthesized via sequential C–H activation/olefin insertion/reduction
开发了一种温和的Rh催化方法,通过还原1-芳基吲唑酮和2-芳基-[4 + 2]环合反应,合成羟基亚氨基官能化的吲唑并[1,2- a ] cinnolines和邻苯并[2,3- a ] cinnolines。 2,3-二氢酞嗪-1,4-二酮与各种硝基烯烃。在无还原剂的条件下,通过连续的C–H活化/烯烃插入/还原反应,合成了目标肟肟修饰的四环稠合肉桂醛。
Asymmetric Michael addition reactions catalyzed by a novel upper-rim functionalized calix[4]squaramide organocatalyst
作者:Ke Yang、Zhiyan Ma、Hong-Xiao Tong、Xiao-Qiang Sun、Xiao-Yu Hu、Zheng-Yi Li
DOI:10.1016/j.cclet.2020.02.057
日期:2020.12
Abstract A novel upper-rim functionalizedcalix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1,3-dicarbonyl compounds to α,β-unsaturated carbonyl compounds in high yields (up to 99 %) and good to excellent enantiomeric excesses (up to 99% ee). The comparative experiments indicated
Enantioselective Conjugate Addition of Both Aromatic Ketones and Acetone to Nitroolefins Catalyzed by Chiral Primary Amines Bearing Multiple Hydrogen-Bonding Donors
of chiral primary amine catalysts bearing multiple hydrogen-bonding donors have been designed and synthesized. The newly developed bifunctional organocatalysts efficiently catalyzed not only enantioselectiveconjugateaddition of aromatic ketones to nitroolefins in good yields (up to 87%) with excellent enantioselectivities (97→99% ee) but also enantioselectiveconjugateaddition of acetone to nitroolefins