Search

Ester is one of the most significant functional groups in organic chemistry and is enclosed in several valued molecules. Usually, esters are prepared through the acid-catalyzed esterification reaction of carboxylic acids with alcohols, transesterification of esters with alcohols, or via activation of carboxylic acids followed by the addition of alcohols. However, these procedures typically imply the excess use of reactants and harsh reaction conditions. Visible light-mediated photoreactions have been disclosed to display a safe, sustainable, and accessible alternative to traditional methods, and to lead new reactivity modes in organic procedures. In this context, we propose a transition metal-based and organic-based photocatalyst-free synthesis of esters from alcohols induced by visible light. The methodology can be carried out using sunlight or artificial visible light as a solar simulator or a blue LED source. [ABSTRACT FROM AUTHOR]

A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields. [ABSTRACT FROM AUTHOR]

Esters and amides, which are functional groups of fundamental importance in organic chemistry are traditionally prepared by reacting carboxylic acid derivatives (carboxylic halides, anhydrides and activated esters) with alcohols and amines, often implying multistep processes. Recently the oxidative esterification and amidation of aldehydes have been raised as sustainable and efficient alternatives to classical synthesis. This digest reports more recent advances in this emergent field. [ABSTRACT FROM AUTHOR]

A novel metal-free oxidative cross esterification of alcohols has been achieved using trichloroisocyanuric acid as an oxidant. The alcohols were converted in situ into their corresponding acyl chlorides, which were then reacted with primary and secondary aliphatic, benzylic and allylic alcohols and phenols. A wide variety of esters was obtained in satisfactory yields. [ABSTRACT FROM AUTHOR]

The reaction tolerates a broad range of substituted aliphatic and aromatic aldehydes as well as benzylic, heterobenzylic, and aliphatic alcohols which may be endowed with various functional groups. Application of chiral alcohols provides optically pure esters without significant racemization. [ABSTRACT FROM AUTHOR]