Isocoumarins are important building blocks in medicinal chemistry. An access to 3-amino-4-halo- or 4-seleno-isocoumarins in a short time (<1 min) with good yields was reported via an electrophilic cyclization of ortho-ynamidyl benzoate esters.
Lewis Acid Catalyzed Electrophilic Aminomethyloxygenative Cyclization of Alkynols with <i>N</i>,<i>O</i>-Aminals
作者:Anrong Chen、Houjian Yu、Jiaqi Yan、Hanmin Huang
DOI:10.1021/acs.orglett.9b04630
日期:2020.1.17
Lewis acid enables the electrophilic carbooxygenative cyclization of alkynols with N,O-aminals. The new process proceeds efficiently under very mild conditions via a pathway that is opposite to classical carbo-metalation. These reactions exhibit broad substrate generality and functional group compatibility, leading to a wide variety of 5-8-membered oxacycles bearing diverse functional groups. The cyclization
Alcohol versus alcohol: A highly stereocontrolled synthesis of substituted morpholines is realized by means of gold‐catalyzed dehydrative allylic cyclization of diols (see scheme for one example; segphos = 5,5′‐bis[di(3,5‐di‐tert‐butyl‐4‐methyoxyphenyl)phosphine]‐4,4′‐bi‐1,3‐benzodioxole). The present methodology represents one of the few examples of enantioselective gold‐catalyzed transformations
Copper(II)-Catalyzed Amidations of Alkynyl Bromides as a General Synthesis of Ynamides and <i>Z</i>-Enamides. An Intramolecular Amidation for the Synthesis of Macrocyclic Ynamides
作者:Xuejun Zhang、Yanshi Zhang、Jian Huang、Richard P. Hsung、Kimberly C. M. Kurtz、Jossian Oppenheimer、Matthew E. Petersen、Irina K. Sagamanova、Lichun Shen、Michael R. Tracey
DOI:10.1021/jo060230h
日期:2006.5.1
method for the coupling of a wide range of amides with alkynyl bromides is described here. This novel amidation reaction involves a catalytic protocol using copper(II) sulfate-pentahydrate and 1,10-phenanthroline to direct the sp-C−N bond formation, leading to a structurally diverse array of ynamides including macrocyclic ynamides via an intramolecular amidation. Given the surging interest in ynamide chemistry
Ti(O-<i>i</i>-Pr)<sub>4</sub>/Me<sub>3</sub>SiCl/Mg-Mediated Reductive Cleavage of Sulfonamides and Sulfonates to Amines and Alcohols
作者:Noriaki Shohji、Tsuyoshi Kawaji、Sentaro Okamoto
DOI:10.1021/ol200740r
日期:2011.5.20
A low-valent titanium generated in situ from Ti(O-i-Pr)4, Me3SiCl, and Mg powder in THF reacted with aryl- and alkyl-sulfonamides of aryl and alkyl amines in a reductive N–S/S–O/S–C bond cleaving pathway to provide the corresponding amines and hydrocarbons (and thiols) derived from the sulfonyl moiety. The reagent could also cleave sulfonates to the corresponding alcohols.