Utilization of CO₂ as a C1 Building Block in a Tandem Asymmetric A³ Coupling-Carboxylative Cyclization Sequence to 2-Oxazolidinones

Abstract

We report a tandem asymmetric aldehyde–alkyne–amine (A3) coupling-carboxylative cyclization sequence for the highly enantioselective synthesis of chiral N-aryl 2-oxazolidinones. This is a rare example of a multicatalyst-promoted asymmetric tandem reaction using CO2 as a C1 synthon. Notably, the copper species and ligand from the upstream A3 reaction are internally reused to facilitate the downstream silver-catalyzed carboxylative cyclization.

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

“…Only in Table 4, entry 1, N-p-methoxyphenylpropargylamine was reported to react in 74% yield, but simple N-phenylpropargylamine did not give any oxazolidinone [134]. In the recent literature, however, an interesting work was performed by Zhou and his research group, who were able to carry out a four component one-pot sequence reaction to give enantioenriched oxazolidinones (Scheme 16) [165]. Authors separately tested the preparation of the enantioenriched propargyl amines and their cyclization, and, when the best conditions were found, they successfully performed the one-pot reaction.…”

Synthesis of Oxazolidin‐2‐ones from Unsaturated Amines with CO2 by Using Homogeneous Catalysis

“…Recently,Z hou and co-workers reported an elegant tandem asymmetricA 3-coupling/carboxylative-cyclization sequence to access chiral N-aryl oxazolidin-2-ones with high enantioselectivities (Scheme 26). [41] The keyt ot he reaction wast hat the copperc omplexf acilitated both the upstream asymmetric A3 reactiona nd the downstream silver-catalyzed carboxylative cyclization reaction. Notably,a nilines, which had shown no re-activity in previousr eports,w erea lso suitable substrates in this process.…”

Recent Developments in Enantioselective Multicatalyzed Tandem Reactions

“…In 2017, Zhou, Wu and Zhou developed a novel route to chiral 2‐oxazolidinones based on a multicatalyzed sequential tandem asymmetric coupling/carboxylative cyclization reaction between alkynes 53 , aromatic aldehydes 136 , aromatic amines 66 and CO 2 . The first step of the process involved at 25 °C in DCE as solvent a chiral copper catalyst in situ generated from 10 mol% of Cu(OTf) 2 and 12 mol% of chiral Pybox ligand 137 that promoted the coupling between alkyne 53 , aromatic aldehyde 122 and aromatic amine 66 to provide the corresponding chiral amine intermediate BY .…”