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

Abstract

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.

Synthesis of Enantioselective Solid Tandem Catalysts with Tethered Molecular Functionalities

“…They can be accelerated by using either acids or tertiary amines, but have also been shown to become more facile upon the addition of both. , The proposed mechanism for these reactions involves the initial displacement of the cyanide group at the carbon atom of the carbonyl in the cyanoester by the amine moiety of the catalyst (the N atom of the quinuclidine ring in the Cd group of our catalyst) to generate an ammonium salt, and that step may be aided by hydrogen bonding of the oxygen atom of the carbonyl to an acidic site (partial protonation; a proposed model for such an interaction is offered in the Table of Content −TOC– graphics). The catalytic cycle is then closed by an attack by the cyanide on the carbonyl carbon of the aldehyde (benzaldehyde in our case) to generate a tertiary cyanoalkoxide, which displaces the amine in the catalyst to form a tertiary cyanocarbonate. , …”

“…The catalytic cycle is then closed by an attack by the cyanide on the carbonyl carbon of the aldehyde (benzaldehyde in our case) to generate a tertiary cyanoalkoxide, which displaces the amine in the catalyst to form a tertiary cyanocarbonate. 45,52 Cyano-ethoxycarbonylations have previously been shown to be promoted by heterogeneous acid−base bifunctional catalysts as well, by combining a tethered diethylamine moiety with the silanol groups of the silico-alumina support. 39,53 Therefore, it seemed appropriate to us to test the possibility of using a better-defined and stronger molecular acidic functionality (the tethered phosphonic acid) to attempt to obtain better catalytic performance.…”

Unique Superbase TBD (1,5,7-Triazabicyclo[4.4.0]dec-5-ene): From Catalytic Activity and One-Pot Synthesis to Broader Application in Industrial Chemistry

“…There are numerous other examples for the successful use of TBD in miscellaneous reactions, − e.g., Wittig and Horner-Wadsworth-Emmons reactions, synthesis of cyanohydrin carbonates and acetates, trifluoromethylation of carbonyl compounds, ring opening reactions of aziridines, and α-hydroxylation of ketones by oxygen . Quite unexpectedly, however, TBD catalyzes also enantioselective reactions, such as the 1,3-isomerization of optically active allyl alcohols, ethers, and chlorides (Scheme ).…”

DFT Study on the Molecular Mechanism, Thermodynamic and Kinetic Parameters of Cycloaddition Reaction of Aziridine with CO2 in the Presence of Organocatalysts (TBD and 7-Azaindole)

“…Among organocatalyst,triazabicyclodecene (1,5,7 Triazabicyclo [4.4.0] dec-5-ene (TBD) is the most widely studied catalyst and has been reported to successfully accelerate various reactionssuch as aminolysis of esters [24], synthesis of cyanohydrin Trends Sci. 20 3 2 ; 20(3): 6520 5 of 20 carbonates [25], cyanosilylation of aldehydes and ketones, Michael reaction, Aldol reaction to list few. It was because of unique nature of TBD we decided to investigate TBD as the catalyst system in this thesis in order to validate whether it is a good candidate to facilitate the reaction or not.…”