Carboxylation with CO₂ via Brook Rearrangement: Preparation of α-Hydroxy Acid Derivatives

Abstract

In the presence of CsF, a wide range of α-substituted α-siloxy silanes were carboxylated under a CO2 atmosphere (1 atm) via Brook rearrangement. A variety of α-substituents including aryl, alkenyl, and alkyl groups were tolerated to afford α-hydroxy acids in moderate-to-high yields. One-pot synthesis from aldehydes using PhMe2SiLi and CO2 was also possible, providing α-hydroxy acids without the isolation of an α-hydroxy silane.

Transition Metal‐Free CO2 Fixation into New Carbon–Carbon Bonds

“…The only two synthetically useful examples have recently been reported by the groups of Sato [26] and Munshi. The only two synthetically useful examples have recently been reported by the groups of Sato [26] and Munshi.…”

“…The only two synthetically useful examples have recently been reported by the groups of Sato [26] and Munshi. [26] The reaction proceeds under 1atm of CO 2 in presence of CsF (XII)a sd esilylating agent, yielding an umber of different substituted a-hydroxy acids 58.T he products are isolated as the corresponding methyl esters 60 a-f,i ng ood to excellent yield (32-97 %). [26] The reaction proceeds under 1atm of CO 2 in presence of CsF (XII)a sd esilylating agent, yielding an umber of different substituted a-hydroxy acids 58.T he products are isolated as the corresponding methyl esters 60 a-f,i ng ood to excellent yield (32-97 %).…”

CO2 Conversion into Esters by Fluoride‐Mediated Carboxylation of Organosilanes and Halide Derivatives

“…Because the C−Si bond features a low polarity, its activation with a fluoride source is necessary to generate a carbanion synthon, which can undergo a carboxylation with CO 2 . Using CsF, the group of Sato recently reported the synthesis of α‐amino acid derivatives (Scheme a), α‐hydroxy acid derivatives (Scheme b), and the carboxylation of benzylsilane derivatives featuring a directing group (Scheme c) . The group of Kondo developed the carboxylation of alkynylsilanes (Scheme d) .…”

Efficient Synthesis of Mandel Acetates by Electrochemical Carboxylation of Benzal Diacetates

“…Carbon dioxide, on the other hand, would also be a useful and favorable carbon source for synthesis of mandelic acid since it is a non‐toxic, abundant, economical, and environmentally benign C1 chemical reagent . There are a few examples of synthesis of mandelic acid and its derivatives using carbon dioxide as a carbon source of the carboxyl group by conventional chemical methods . Because of chemical stability of carbon dioxide, complicated or highly‐reactive reagents under severe or harsh reaction conditions would be frequently necessary.…”