Enantioselective Bromocyclization of Allylic Amides Catalyzed by BINAP Derivatives
摘要:
A highly enantioselective bromocyclization of allylic amides with N-bromosuccinimide (NBS) was developed with DTBM-BINAP as a catalyst, affording chiral oxazolines with a tetrasubstituted carbon center in high yield with up to 99% ee. By utilizing the bromo substituent as a handle, the obtained compounds were converted to synthetically useful chiral building blocks.
Gold-Catalyzed Deoxygenative Nazarov Cyclization of 2,4-Dien-1-als for Stereoselective Synthesis of Highly Substituted Cyclopentenes
作者:Chung-Chang Lin、Tse-Min Teng、Chung-Chih Tsai、Hsin-Yi Liao、Rai-Shung Liu
DOI:10.1021/ja806415t
日期:2008.12.3
annulation products reveals evidence for the participation of Nazarov cyclization. This deoxygenative cyclization is extensible to a tandemintramolecularcyclization/nucleophilic addition cascade, giving polycyclic carbo- or oxacyclic compounds with controlled stereochemistry. This new gold catalysis is applied to a short synthesis of natural compounds of the brazilane family, including brazilane, O-trimethyl-
Highly regioselective Heck reactions of heteroaryl halides with electron-rich olefins in ionic liquid
作者:Wen Pei、Jun Mo、Jianliang Xiao
DOI:10.1016/j.jorganchem.2005.03.008
日期:2005.8
Palladium-catalyzed Heck reactions of the heteroaryl halides, halopyridines, bromoquinoline and bromothiophenes, with the electron-richolefins vinyl ethers and allyl alcohol were shown to give essentially only the branched olefins in an imidazolium ionic liquid, whereas in molecular solvents a mixture of regioisomers was formed. The method obviates the need for aryl triflates and stoichiometric inorganic
Synthesis of Quaternary Carbon Centers via Hydroformylation
作者:X. Sun、K. Frimpong、K. L. Tan
DOI:10.1021/ja1036226
日期:2010.9.1
application of hydroformylation to the synthesis of quaternary carbon centers is reported. The synthesis of the highly substituted carbon is achieved by applying a catalyticamount of 1. Ligand 1 serves as a catalyticdirectinggroup by covalently and reversibly binding to both the substrate and catalyst. The intramolecular nature of the directinggroup strategy accelerates the hydroformylation reaction
we report that the [4 + 1] reaction of common dienes and CO cannot work, at least under the catalysis of [Rh(cod)Cl]2. However, using cyclopropyl-capped dienes (also named allylidenecyclopropanes) as substrates, the corresponding [4 + 1] reaction with CO proceeds smoothly in the presence of [Rh(cod)Cl]2. This [4 + 1] reaction, with a broad scope, provides efficient access to five-membered carbocyclic
A highly enantioselective bromocyclization of allylic amides with N-bromosuccinimide (NBS) was developed with DTBM-BINAP as a catalyst, affording chiral oxazolines with a tetrasubstituted carbon center in high yield with up to 99% ee. By utilizing the bromo substituent as a handle, the obtained compounds were converted to synthetically useful chiral building blocks.