Palladium- and Ruthenium-Catalyzed Cycloisomerization of Enynamides and Enynhydrazides: A Rapid Approach to Diverse Azacyclic Frameworks
作者:P. Ross Walker、Craig D. Campbell、Abid Suleman、Greg Carr、Edward A. Anderson
DOI:10.1002/anie.201304186
日期:2013.8.26
I want to ride my azacycle: The title reaction of enynamides affords a wide diversity of azacycles. The reactions are high‐yielding, highly stereoselective, and proceed rapidly under mild reaction conditions. Equivalent transformations using enynhydrazides offer new routes to pyrazole and indazole scaffolds. Boc=tert‐butoxycarbonyl, EWG=electron‐withdrawing group, Ns=4‐nitrobenzenesulfonyl, Ts=4‐toluenesulfonyl
A unique 1,7-S- and Se-shift reaction under Pummererreaction conditions of 4-alkenyl-3-sulfinyl- and seleninylpyrroles was described. The usual Pummererreaction of 4-(alkenylaminomethyl)-3-phenylsulfinylpyrroles and a successive reaction with tetrabutylammonium hydroxide (TBAH) yielded either pyrrolo[3,2-c]azepines or N-pyrrol-3-ylmethyl-N-(4-hydroxy-3-sulfanylpropyl)-p-toluenesulfonamides (diols)
Au-Catalyzed Piperidine Synthesis via Tandem Acyloxy Migration/Intramolecular [3 + 2] Cycloaddition of Enynyl Esters
作者:Huaiji Zheng、Xing Huo、Changgui Zhao、Peng Jing、Juan Yang、Bowen Fang、Xuegong She
DOI:10.1021/ol202746s
日期:2011.12.16
An Au-catalyzed tandem protocol involving enynyl ester isomerization and subsequent intramolecular [3 + 2] cyclization has been developed. This strategy provides an efficient approach for the synthesis of polyfunctional piperidines, which are subunits of many bioactive molecules.
Hf(IV)-Catalyzed Enantioselective Epoxidation of <i>N</i>-Alkenyl Sulfonamides and <i>N</i>-Tosyl Imines
作者:José Luis Olivares-Romero、Zhi Li、Hisashi Yamamoto
DOI:10.1021/ja211880s
日期:2012.3.28
Asymmetric epoxidation of allylic and homoallylic amine derivatives catalyzed by Hf(IV)-bishydroxamic acid complexes is described. Under similar conditions, aldimine and ketimine produced oxaziridines. The sulfonyl group is demonstrated to be an effective directing group for these transformations.
A general effective organocatalyzed synthesis of enantioenriched morphans with up to 92% ee was developed. The morphan scaffold was constructed in a one-pottandem asymmetric organocatalyzed Michaeladditionfollowed by a domino Robinson annulation/aza-Michael intramolecular reaction sequence from easily available starting materials.