The synthetic uses of carboxylic acids and their derivatives

CuH-Catalyzed Regio- and Enantioselective Hydrocarboxylation of Allenes: Toward Carboxylic Acids with Acyclic Quaternary Centers

“…All-carbon quaternary stereocenters, a structural feature that can impart significant chemical and biological impact to a molecule, are critical to many synthetic and medicinal applications. − Consequently, catalytic and enantioselective approaches for constructing all-carbon quaternary centers, especially functionalized stereocenters, are highly desirable. − Carboxylic acids, a chemically versatile functional group, that can bear an α-stereogenic center often serve as useful synthetic intermediates. − More importantly, α-chiral carboxylic acid derivatives themselves constitute an essential class of compounds in pharmaceutical, agrochemical, and natural product arenas (Figure A). − Methods for generating enantioenriched α-chiral carboxylic acids have long been sought after . Prominent synthetic strategies targeting α-chiral carboxylic acids or esters via asymmetric catalysis include hydrogenation of α,β-unsaturated carboxylic acids, carbene-induced C–H insertion with diazoacetates, − enantioselective protonation , or hydrogen atom transfer processes, and α-functionalization of carboxylic acid derivatives. − Nonetheless, catalytic access to enantioenriched acyclic carboxylic acids or esters featuring an all-carbon α-quaternary stereocenter remains challenging. , In this regard, common synthetic methods include allylic alkylation of geometrically pure alkenes, − often with superstoichiometric organometallic reagents, and α-functionalization of carboxylic acid derivatives, − …”

Synthesis of α‐Quaternary Carboxylic Acids through Cu‐Catalyzed Hydrocarboxylation of Allenes with Diisobutylaluminum Hydride and Carbon Dioxide

“…Hydrocarboxylation of CÀ C multiple bonds with carbon dioxide (CO 2 ) is a highly reliable and powerful method for synthesizing carboxylic acids, which are valuable chemical building blocks used in various industrial and commercial applications. [1,2] This approach is particularly appealing because it uses CO 2 , which, in addition to being a sustainable and abundant source of carboxyl groups, is environmentally friendly and nontoxic. [3] Allenes are prominent unsaturated substrates for hydrocarboxylation reactions because of their versatility as precursors for structurally diverse functionalized molecules, making them highly valuable for organic synthesis.…”

Geometry-Constrained N,N,O-Nickel Catalyzed α-Alkylation of Unactivated Amides via a Borrowing Hydrogen Strategy

“…Traditionally, the transformation proceeds in the presence of strong bases, such as LDA or sodium amide. However, these alkylating processes are confronted with the concept of green chemistry in some content, suffering from the toxic nature of numerous halide electrophiles and producing stoichiometric amounts of undesirable salts . Therefore, developing a practical, green, and atom-economical enolate alkylation process is highly desirable.…”