| a-Aryl(heteroaryl)nitriles are useful precursors to pharmaceutical and bioactive compounds.They are known as important synthons in organic synthesis which can be readily converted to carboxylic acids,amides,aldehydes,amines ketones and heterocycles.Thus,?-aryl(heteroaryl)nitriles are a class of important synthetic targets.The current synthetic methods for producing a-aryl(heteroaryl)nitriles are the cross-coupling of aryl(heteroaryl)electrophiles with nitrile nucleophiles;reactions between aryl(heteroaryl)nucleophiles and nitrile electrophile;benzylic cyanation;Michael addition and others.Because of their generality and versatility,transition-metal-catalyzed cross-coupling reactions between aryl halides and alkylnitriles are more practical than other synthetic methods.However,this powerful technology has rarely been applied to the synthesis of a-heteroaryl nitriles.For example,there is lack of efficient ways to access a-indole nitriles.Hence a general process for synthesizing both a-aryl-and heteroaryl nitriles is highly desirable but remains elusive.Herein we describe a general protocol for the synthesis of a-aryl-and heteroaryl nitriles.Specifically,the simple treatment of a mixture of aryl(heteroaryl)sulfoxides and ?-stannyl nitriles with an anhydride produces a diverse array of a-aryl(heteroaryl)nitriles(>60 examples).Notable features of this reaction include its remarkably low reaction temperature(-78 ?),superior functional group compatibility,and highly transformable products.This technology was applied to the synthesis of tryptamines.DFT mechanistic study suggests that the activation of sulfoxides by anhydride to generate an electrophilic species is the rate determing step of the reaction. |
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