The Domino Oxa-Michael Addition–Aldol Reaction: Access to Variably Substituted Tetrahydroxanthenones
作者:Ulrike K. Ohnemüller (née Schmid)、Carl F. Nising、Martin Nieger、Stefan Bräse
DOI:10.1002/ejoc.200500887
日期:2006.3
Tetrahydroxanthenones represent the core of many natural products, most of which exhibit interesting biological activities. In the course of our synthetic efforts towards the total synthesis of the secalonic acids, which contain two of these tricyclic units, we have investigated the influence of substituents on the one-step dominooxa-Michaeladdition–aldolreaction leading to tetrahydroxanthenones
Synthesis of the Tricyclic Picrotoxane Motif by an Oxidative Cascade Cyclization
作者:Jingming Cao、Waygen Thor、Shenkun Yang、Mengxun Zhang、Wenli Bao、Lizhi Zhu、Wei Yang、Yuen-Kit Cheng、Chi-Sing Lee
DOI:10.1021/acs.orglett.9b01806
日期:2019.6.21
An oxidative cascade cyclization of β-keto esters has been developed for the construction of the tricyclic picrotoxane motif in a single step, and DFT calculations suggested a possible cationic cyclization mechanism. This cascade cyclization can be operated on a 20 g scale to obtain a 77% total yield of the tricyclic products, which in turn can be converted to versatile intermediates for further elaboration
1-Amino-3-siloxy-1,3-butadienes: Highly Reactive Dienes for the Diels−Alder Reaction
作者:Sergey A. Kozmin、Jacob M. Janey、Viresh H. Rawal
DOI:10.1021/jo981563k
日期:1999.4.1
heteroatom-containing dienes with several useful properties. These dienes can be prepared efficiently by deprotonation of readily available vinylogous amides with potassium hexamethylsilazide, followed by silylation of the corresponding potassium enolates. This protocol has been found to be quite general for the preparation of various dienes containing different silyl and amino groups. Amino siloxy dienes readily
Catalytic Enantioselective Total Synthesis of (−)-Platyphyllide and Its Structural Revision
作者:Shiharu Hiraoka、Shinji Harada、Atsushi Nishida
DOI:10.1021/jo1003746
日期:2010.6.4
The catalytic asymmetric totalsynthesis of platyphyllide has been accomplished. A key highly substituted cyclohexene derivative has been obtained by the catalytic asymmetric Diels−Alder reaction of Danishefsky diene with an electron-deficient alkene. The Diels−Alder adduct was converted to a protected cyclohexane-1,3-dione in chiral form by catalytic Ito−Saegusa oxidation. Although the reported structure
Chemoenzymatic Late‐Stage Modifications Enable Downstream Click‐Mediated Fluorescent Tagging of Peptides
作者:Alessandro Colombano、Luca Dalponte、Sergio Dall'Angelo、Claudia Clemente、Mohannad Idress、Ahmad Ghazal、Wael E. Houssen
DOI:10.1002/anie.202215979
日期:——
suitable for copper-catalyzed azide-alkyne cycloaddition, metathesis, and inverse-electron-demand Diels-Alder (IEDDA) reactions. A 10-mer tryptophan-containing macrocyclic peptide was tailored by AcyF, and the resulting modified peptide was successfully labelled with a tetrazine–fluorescein conjugate by IEDDA.