Asymmetric cyano-ethoxycarbonylation of aldehydes catalyzed by self-assembled titanium catalyst

Immobilization of an acid–base cooperative catalyst on MCM-41 as a heterogeneous approach for the asymmetric cyanoethoxycarbonylation of isatins

Heterogenization of chiral quinine-thiourea catalyst for enantioselective cyanation reaction. The catalyst is found to be efficient and recyclable up to five times with retention of its catalytic activity.

TBD- or PS-TBD-Catalyzed One-Pot Synthesis of Cyanohydrin Carbonates and Cyanohydrin Acetates from Carbonyl Compounds

Cyanation reactions of carbonyl compounds with methyl cyanoformate or acetyl cyanide catalyzed by 5 mol % of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) were examined. Using methyl cyanoformate, the corresponding cyanohydrin carbonates were readily obtained in high yield for aromatic and aliphatic aldehydes and ketones. Similar results were obtained when acetyl cyanide was used as the cyanide source. The polymer-supported catalyst, PS-TBD, also acted as a good catalyst for this reaction. PS-TBD was easily recovered and reused with minimal activity loss.

Aminomethylation of BINOL with methyleneiminium salts

A new method for synthesizing chiral 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with high enantiomeric excess is described. The procedure consists of bis-lithiation of diprotected (S)- or (R)-1,1′-bis(2-naphthol) followed by treatment of the intermediate with methyleneiminium salts. Mild reaction conditions prevent racemization and provide 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols or 3-(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with an enantiomeric excess >99%.

Asymmetric cyanation of activated olefins with ethyl cyanoformate catalyzed by a modular titanium catalyst

Asymmetric cyanation of a class of easily available olefins with a favorable cyanide source ethyl cyanoformate (CNCOOEt) was realized by an interesting modular catalyst. High yields and ee values were obtained for a range of substrates under solvent-free and mild reaction conditions. The products obtained could be easily transformed to the enantioenriched useful intermediates 5, 6, and pharmaceutically important gamma-aminobutyric acid 7.