Intramolecular [3 + 2]-Cycloadditions of Azomethine Ylides Derived from Secondary Amines via Redox-Neutral C–H Functionalization
作者:Kempegowda Mantelingu、Yingfu Lin、Daniel Seidel
DOI:10.1021/ol502918g
日期:2014.11.21
Azomethine ylides are accessed under mild conditions via benzoic acid catalyzed condensations of 1,2,3,4-tetrahydroisoquinolines or tryptolines with aldehydes bearing a pendent dipolarophile. These intermediates undergo intramolecular [3 + 2]-cycloadditions in a highly diastereoselective fashion to form polycyclic amines with four new stereogenic centers. Challenging substrates such as piperidine,
Organocatalytic asymmetric intramolecular [3+2] cycloaddition: A straightforward approach to access multiply substituted hexahydrochromeno[4,3-b]pyrrolidine derivatives in high optical purity
作者:Nan Li、Jin Song、Xi-Feng Tu、Bin Liu、Xiao-Hua Chen、Liu-Zhu Gong
DOI:10.1039/c002369h
日期:——
A chiral phosphoric acid-catalyzed intramolecular 1,3-dipolar cycloaddition of 4-(2-formylphenoxy)butenoates with amino esters provides hexahydromeno[4,3-b]pyrrolidine derivatives in high enantioselectivity (up to 94% ee).
Intramolecular Tandem Seleno-Michael/Aldol Reaction: A Simple Route to Hydroxy Cyclo-1-ene-1-carboxylate Esters
作者:Piotr Banachowicz、Jacek Mlynarski、Szymon Buda
DOI:10.1021/acs.joc.8b01853
日期:2018.9.21
Intramolecular tandem seleno-Michael/aldol reaction followed by an oxidation–elimination process can be an efficient tool for the construction of hydroxy cyclo-1-ene-1-carboxylate esters from oxo-α,β-unsaturated esters. Generation of lithium selenolate from elemental selenium and n-BuLi provides a simple and efficient one-pot access to cyclic endo-Morita–Baylis–Hillman adducts.
Scope of the Asymmetric Intramolecular Stetter Reaction Catalyzed by Chiral Nucleophilic Triazolinylidene Carbenes
作者:Javier Read de Alaniz、Mark S. Kerr、Jennifer L. Moore、Tomislav Rovis
DOI:10.1021/jo702313f
日期:2008.3.1
A highly enantioselective intramolecular Stetter reaction of aromatic and aliphatic aldehydes tethered to different Michael acceptors has been developed. Two triazolium scaffolds have been identified that catalyze the intramolecular Stetter reaction with good reactivity and enantioselectivity. The substrate scope has been examined and found to be broad; both electron-rich and -poor aromatic aldehydes
design and prediction of enzyme promiscuity to access transformations not observed in nature remains a long‐standing challenge. Herein, we present the first example of an intramolecular stereoselective Stetter reactioncatalyzed by benzaldehyde lyase, guided by the rational structure screening of various ThDP‐dependent enzymes using molecular dynamics (MD) simulations. After optimization, high productivity