Stereoselective Synthesis of Oxabicyclo[2.2.1]heptenes via a Tandem Dirhodium(II)-Catalyzed Triazole Denitrogenation and [3 + 2] Cycloaddition
作者:Hao Yuan、Jianxian Gong、Zhen Yang
DOI:10.1021/acs.orglett.6b02703
日期:2016.11.4
A novel synthetic strategy for the diastereoselective synthesis of structurally diverse oxabicyclo[2.2.1]heptenes has been developed, featuring a tandemreaction combining a Rh-catalyzed triazole denitrogenation and a novel type of [3 + 2] cycloadditionreaction. This tandemreaction was thought to proceed via a five-membered oxonium ylide intermediate, which was formed by the intramolecular nucleophilic
Tandem ring‐closing enyne metathesis (RCEM)/ring‐closing olefin metathesis (RCM) of tetraenynes with Grubbs second‐generation catalyst, followed by elimination, was found to be a new and efficient synthetic approach to biaryl compounds. A preliminary asymmetric version of this approach, which used homochiral Ru–alkylidene catalysts, is also presented.
The synthesis of several natural products’ frameworks is carried out by means of a diastereoselective intramolecular Pauson–Khand reaction promoted by molecular sieves. Diastereoselectivity is achieved only if a coordinating group is present at a convenient distance from the alkene moiety. Naphthalenes can be obtained directly under refluxing toluene conditions.
Stereoselective Synthesis of Kalafungin Based on CuI‐Catalyzed Tandem Reactions of Arylethynes Containing an Ortho‐(1‐Hydroxyethyl) Substituent with Alkyl Diazoacetates
An isochromene synthesis is developed utilizing a cascade reaction involving a CuI catalyzed coupling reaction between an alkyne and diazoacetate followed by allenoate isomerization and subsequent oxa-Michael addition. The cascade sequence was also demonstrated for the synthesis of naphthalenes. Furthermore, the methodology developed herein was applied toward a stereoselectivesynthesis of pyranonaphthoquinone
异色烯合成是利用级联反应开发的,该反应涉及炔烃和重氮乙酸酯之间的 CuI 催化偶联反应,然后是烯丙酸酯异构化和随后的氧杂-迈克尔加成。级联序列也被证明用于合成萘。此外,本文开发的方法应用于吡喃萘醌卡拉芬净的立体选择性合成。