Carboxylation of Alkenyl Boronic Acids and Alkenyl Boronic Acid Pinacol Esters with CO₂ Catalyzed by Cuprous Halide

Abstract

A cuprous halide catalysed carboxylation of alkenyl boronic acids and alkenyl boronic acid pinacol esters under CO 2 , affording the corresponding α, -unsaturated carboxylic acids in good yield, has been developed. The potassium (E)- [a] . The current research interests of his group include CO 2 utilization in organic synthesis, organic electrochemistry, and modification of semiconductor oxides for energy and resource utilization.Scheme 2. The reaction of (E)-styrylboronic acid 1a, (E)-4,4,5,5-tetramethyl-2-styryl-1,3,2-dioxaborolane 3a, (E)-trifluoro(styryl)borate 4 with CO 2 in the optimal conditions. a Isolated yield. acid and p-methoxy substituted styrylboronic acid provided lower yields (56 %, 2c and 64 %, 2d), probably because electronic effect promoted the generation of protodeboronation Scheme 3. The substrates scope of alkenyl boron acids. Reactions were carried out by using alkenyl boronic acid 1 (1.0 mmol), cat. CuCl (3.0 mol %), base KOMe (2.0 equiv.) in DMA at 70°C for 24 h under 1 atm CO 2 . Isolated yields were reported.

Challenges and recent advancements in the transformation of CO2into carboxylic acids: straightforward assembly with homogeneous 3d metals

“…Compared to the previous studies, they reported the use of alkenyl boric acids and alkenyl potassium trifluoroborates instead of alkenyl boronic acid esters as the starting materials for carboxylation reactions. [256][257][258][259][260][261][262][263][264][265] By this strategy, a,b-unsaturated carboxylic acids were synthesized, which have numerous applications in the pharmaceutical industry or as intermediates in organic synthesis. 250 After the optimizations, it was found that styryl boronic acid (270) reacted with CO 2 to form cinnamic acid (271) in 92% yield by using CuCl and KOMe in DMA at 70 1C for 24 h (Scheme 43).…”

Recent Advances in Copper‐Catalyzed Carboxylation Reactions with CO2

“…The scope of copper‐catalyzed carboxylation of the organoboron substrates was further expanded by Mo and co‐workers, who utilized alkenyl boric acids and alkenyl boronic acid pinacol esters as reactive partners with CO 2 under copper catalysis (Scheme 7). [19] The simple CuCl was used as catalyst, enabling the production of α,β‐unsaturated carboxylic acids in moderate to high yields. The potassium (E)‐trifluoro(styryl)borate also served as a suitable substrate under the current catalytic system.…”