Ti-Catalyzed Radical Dehydroxylative Alkylation,Vinylation Of Tertiary Alcohols And Glycosyl Radical Alkylation Reaction

Titanium-catalyzed coupling reactions of C-O electrophiles are developing rapidly,the reaction has been widely used in the activation of C-O bonds such as aldehydes,ketones,and epoxy,as well as the activation of a few active alcohol such as allyl alcohol and benzyl alcohol.Under the existing catalytic systems,the radical activation of tertiary alcohols and Glycosyls is extremely challenging.Chapter 1: We introduce the development process and research status of titaniumcatalyzed C-O electrophiles in coupling reactions,and summarize possible reaction mechanism and the substrate applicability.Chapter 2: We have studied the radical deoxyalkylation of inactive tertiary alcohols and establish a new method to construct all-carbon quaternary carbon centers directly from tertiary alcohols.Controlled experiments and theoretical calculations reveal the reaction mechanism of Ti-catalyzed C-O bond homolytic cleavage of tertiary alcohols to generate tertiary carbon radicals.This method provides possibilities for the efficient application of tertiary alcohols in the fields of organic synthesis and medicinal chemistry.Chapter 3: We develop dehydroxylative vinylation reaction of tertiary alcohols and,thus,establish a new method for the construction of vinylated quaternary allcarbon centers.The method is highly selective for the vinylation of tertiary alcohols,leaving secondary/primary alcohols intact.The use of a mixture of trans-and cishaloalkenes gives the same trans-products.Chapter 4: We develop dehydroxylative radical C-C bond-forming reaction of Glycosyls and therefore establish a new method for constructing C-alkyl glycosides.Although the method is currently immature and the vast majority of substrates do not give ideal results,we are working on a more careful and systematic optimization of the reaction conditions.