Asymmetric Construction of α-Substituted β-Hydroxy Lactones via Ni Catalyzed Decarboxylative Addition Reaction

Abstract

We described a Ni-bidentate oxazoline catalyzed highly enantio- and diastereoselective decarboxylative aldol reaction of 2-oxotetrahydrofuran-3-carboxylic acid/2-oxochromane-3-carboxylic acid derivatives with different kinds of carbonyls. Under optimal reaction conditions, α-substituted β-hydroxy butyrolactones and dihydrocoumarins with an all-carbon quaternary stereocenter have been generated with high levels of functional-group compatibility. Furthermore, proficient transformations of products were also described, in which an aliphatic tertiary alcohol and a multi-substituted 1,4-diol were smoothly constructed through hydrogenation and ring-opening reaction, respectively.

Asymmetric synthesis of δ-substituted-β-keto esters and β-substituted ketones via carboxyl-assisted site- and enantio-selective addition reactions

“…Based on previous work 5 e ,6 and the results obtained herein, a plausible hypothesis as to the origin of the observed site- and enantio-selectivity was proposed. As shown in Fig.…”

“…Great achievements have been made in this field by employing unmodified carboxylic acids, malonic acid half thioesters and α-keto acids as nucleophilic precursors; 5 we also described a series of research studies on malonic acid/α-carboxy ester-involved catalytic asymmetric decarboxylative addition reactions. 6 In most cases, the carboxy group of nucleophiles can be considered as both an activating and a leaving group which is extruded traceless as CO 2 from the reaction mixture. Besides, considering the strong interaction between the carboxy group and the metal cation, the former may also act as a directing group under metal salt catalysis (Fig.…”

Further developments of β,γ-unsaturated α-ketoesters as versatile synthons in asymmetric catalysis

“…In the same year, Hu and Jiang et al. described a decarboxylative aldol reaction of β,γ -unsaturated α -ketoesters 1c with 2-oxotetrahydrofuran-3-carboxylic acid 35/2-oxochromane-3-carboxylic acid derivatives 37 ( Scheme 4 D) ( He et al., 2021b ). The desired product α -substituted β -hydroxy butyrolactones 36 and dihydrocoumarins 38 were well generated in the presence of a bidentate oxazoline-Ni(II) catalysis.…”