One-Pot Double [3 + 2] Cycloadditions for Diastereoselective Synthesis of Pyrrolidine-Based Polycyclic Systems
作者:Xiaofeng Zhang、Weiqi Qiu、Xiaoming Ma、Jason Evans、Manpreet Kaur、Jerry P. Jasinski、Wei Zhang
DOI:10.1021/acs.joc.8b02046
日期:2018.11.2
Sequential inter- and intramolecular [3 + 2] cycloadditions of azomethine ylides are developed for the one-pot and diastereoselectivesynthesis of highly condensed heterocyclic systems containing pyrrolidine and up to seven stereocenters. It has high synthetic efficiency and operational simplicity, and only water was generated as a byproduct.
efficient catalyst for intramolecular Povarov reactions. Polycyclic amines containing three contiguous stereogenic centers were obtained with excellent stereocontrol in a single step from secondary anilines and aldehydes possessing a pendent dienophile. These transformations constitute the first examples of catalytic enantioselective intramolecular aza‐Diels–Alder reactions.
Stereochemically Rich Polycyclic Amines from the Kinetic Resolution of Indolines through Intramolecular Povarov Reactions
作者:Chang Min、Daniel Seidel
DOI:10.1002/chem.201602314
日期:2016.7.25
Under control of a chiral Brønsted acid catalyst, racemic indolines undergo intramolecular Povarov reactions with achiral aromaticaldehydes bearing a pendent dienophile. One enantiomer of the indoline reacts preferentially, resulting in the highly enantio‐ and diastereoselective formation of polycyclic heterocycles with four stereogenic centers. This kinetic resolution approach exploits the differential
Photoredox-Catalyzed Ketyl–Olefin Coupling for the Synthesis of Substituted Chromanols
作者:Eleonora Fava、Masaki Nakajima、Anh L. P. Nguyen、Magnus Rueping
DOI:10.1021/acs.joc.6b01006
日期:2016.8.19
A visible light photoredox-catalyzed aldehyde olefin cyclization is reported. The method represents a formal hydroacylation of alkenes and alkynes and provides chromanol derivatives in good yields. The protocol takes advantage of the double role played by trialkylamines (NR3) which act as (i) electron donors for reducing the catalyst and (ii) proton donors to activate the substrate via a proton-coupled
报道了可见光光氧化还原催化的醛烯烃环化。该方法代表烯烃和炔烃的正式加氢酰化,并以良好的收率提供色原醇衍生物。该协议利用了三烷基胺 (NR 3 ) 所起的双重作用,它们充当 (i) 电子供体以减少催化剂和 (ii) 质子供体通过质子耦合电子转移激活基板。
作者:Amit A. Kudale、David O. Miller、Louise N. Dawe、Graham J. Bodwell
DOI:10.1039/c1ob05867c
日期:——
A series of pentacyclic heterocyclic systems (15 examples, 69–89%) have been synthesized using intramolecular Povarov reactions involving 3-aminocoumarins and O-cinnamylsalicylaldehydes. The Povarov adducts are formed with high selectivity for the trans,trans relative stereochemistry in the newly-formed [6,6] fused ring system. One example of a Povarov adduct featuring a new [6,5] fused ring system is reported. In this case, cis,trans relative stereochemistry was preferred.