O-Methoxycarbonyl Cyanohydrin as a New Protective Group for Carbonyls

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.

One-pot synthesis of cyanohydrin derivatives from alkyl bromides via incorporation of two one-carbon components by consecutive radical/ionic reactions

The consecutive radical/ionic reaction consisting of radical formylation of alkyl bromides and nucleophilic addition of a cyanide ion was investigated, which gave moderate to good yields of cyanohydrin derivatives in one-pot.

Tetrahydropyranyl ether (THPE) formation in hydroxyl group protection and conversion to other useful functionalities

This short review highlights the various methods of formation of tetrahydropyranyl ethers (THPEs) as a method for the protection of simple alcohols as well as a diverse range of complex molecules, using a variety of reagents and reaction conditions including their direct conversion to other useful functionalities.

Lewis base promoted intramolecular acylcyanation of α-substituted activated alkenes: construction of ketones bearing β-quaternary carbon centers

A novel phosphine-promoted intramolecular acylcyanation of α-substituted activated alkenes has been developed, which provides a unique access to densely functionalized acyclic ketones bearing β-quaternary carbon centers with a remarkable feature that both α- and β-positions of activated alkene are functionalized.

Dual Lewis Acid−Lewis Base Activation in Enantioselective Cyanation of Aldehydes Using Acetyl Cyanide and Cyanoformate as Cyanide Sources

Dual activation by a chiral Lewis acid and an achiral or chiral Lewis base enabled cyanation of both aromatic and aliphatic aldehydes with acetyl cyanide and ethyl cyanoformate to provide direct access to O-acetylated and O-alkoxycarbonylated cyanohydrins, respectively, under mild conditions. With a combination of a Ti-salen catalyst and Et3N, benzaldehyde was converted to the O-acetylated cyanohydrin with 94% ee within 10 h at -40 degrees C in 89% isolated yield.