Radical-type Decarbonylation Of Aldehydes And Its Application In Alkylative Esterification Of Alkenes/Alkylative Alkylation Of Alkynes

Direct difunctionalization of alkenes or alkynes,is capable of introducing two functionalities or atoms,construction new chemical bonds,which not only increases the diversity of products,but also reduces the synthetic steps and the amount of metal reagents,and improves the efficiency of synthesis,thus this topic has attracted much attention in recent years.In this text,we speculated the formation of alkyl radicals by oxidative decarbonylation of aldehydes,and its application in alkylative esterification of alkenes/alkylative arylation of alkynes.The details are as follows:A convenient Co-catalyzed threecomponent decarbonylative alkylative esterification of styrene derivatives with aliphatic aldehydes and iodobenzene diacetate to provide chain elongated benzyl esters was developed.Readily available aliphatic aldehydes including sugar analogs were decarbonylated into 1^o,2^oand 3^oalkyl radicals readily for the cascade construction of C?sp³?-C?sp³?and C?sp³?-O bonds.This alkylative esterification not only produced various acetates with iodobenzene diacetate playing a dual role of oxidant and acetate anion source,but also incorporated different?hetero?aromatic acid by ligand exchange to prepare the corresponding benzoates.A mechanism including the Co ^II-Co ^III-Co ^Iinterconversion was proposed based on the mechanistic studies.The application of cheap and readily available aliphatic aldehydes as alkyl source,convenient experimental operation and versatile synthetic utilities of chain elongated benzyl esters,would render this decarbonylative alkylative esterification cascade reaction attractive for organic synthesis and medicine chemistry.A convenient Cu-promoted threecomponent decarbonylative alkylative arylation of terminal alkynes with aliphatic aldehydes and arenes to provide trisubstituted olefins was developed,with good chemo,regio-and stereoselectivities.Readily available aliphatic aldehydes including sugar derivatives were decarbonylated into 1^o,2^oand 3^oalkyl radicals readily for the cascade construction of C?sp³?-C?sp²?and C?sp²?-C?sp²?bonds.A pathway including the nucleophilic addition of alkyl radicals to C?C bond and the subsequent homolytic aromatic substitution with arenes,to realize the dual C?sp²?-H bond transformation,was proposed and wellsupported based on the mechanistic studies.The application of cheap and readily available aliphatic aldehydes as alkyl source,convenient experimental operation for the alkyl radical generation,dual C?sp²?-H bond transformation strategy and versatile synthetic utilities of the chain elongated tri-substituted olefins,would render this decarbonylative alkylative arylation attractive for organic synthesis and green chemistry.