65466-77-5

Upstream product

• 2216-51-5 (-)-menthol 
• 97-72-3 2-Methylpropionic anhydride 
• 79-31-2 isobutyric Acid 

Downstream Products

• 71899-70-2 (R)-(+)-3-methyl-1-(4-methylphenylsulfinyl)-2-butanone 
• 68326-59-0 3-Methyl-1-((S)-toluene-4-sulfinyl)-butan-2-one 

Relevant academic research and scientific papers

Fluorous 4-N,N-dimethylaminopyridine (DMAP) salts as simple recyclable acylation catalysts

The use of an easily accessible fluorous salt of DMAP, 1-R, as an active and recyclable acylation catalyst, under simple conditions has been reported. The recyclability of organic- and metal-based catalysts is of prime interest for the development of sustainable synthesis processes. The alcohol and the anhydride were mixed in a 10 mL round-bottomed flask and 1-R was added. The DMAP-catalyzed esterification reaction of an alcohol is performed in nonpolar solvents with an anhydride as the acyl donor, in the presence of a base in stoichiometric amounts. The simplicity of the process (readily accessible catalyst, easy to handle and to recover) makes it an attractive alternative for cleaner and safer acylation reactions, which could be used with asymmetric dialkylaminopyridines, or in other transformations, such as the Baylis Hillman reaction.

Pyridinium saccharinate salts as efficient recyclable acylation catalyst: A new bridge between heterogeneous and homogeneous catalysis

It is important to find a way for separation of concerned chemicals from product mixture after reaction, in order to avoid spreading harmful chemicals to society. The homogeneous nature of DMAP-catalyzed acylation still suffers from the problems of catalyst separation and/or residual DMAP contamination. DMAP causes acute dermal toxicity, whereas the corresponding DMAP salt exhibits only slight irritation to the skin. Very recently, we found that the DMAP saccharinate salt is also great recyclable catalyst, whose acylation of alcohols has been successfully and effectively carried out 10 times without loss in activity. This report covers our comprehensive studies on using the pyridinium saccharinate salts as efficient recyclable acylation catalysts including 4-N,N-dimethylaminopyridinium saccharinate (A), 4-(1-pyrrolidinyl) pyridinium saccharinate (B), 2-N,N-dimethylaminopyridinium saccharinate (C), and pyridinium saccharinate (D). Their structure and reactivity have been studied. The salts A, C, and D contain very interesting seven-membered synthon showing multiple H-bonding interactions for pair of pyridinium cation and saccharinate anion in the solid state. The salt B exhibits H-bonding interaction of N(sac) ... H-N(py) in the solid state, instead of seven-membered synthon. The catalytic reactivity studies show that salts A and B are both very effective, with salt B even better in reactivity, and are both recyclable in the esterification of a variety of alcohols, under solvent-free and base-free conditions at room temperature.

The phosphate-carboxylate mixed-anhydride method: A mild, efficient process for ester and amide bond construction

A highly efficient carboxylate-phosphate anhydride pathway is described for the direct, economical synthesis of esters and amides from carboxylic acids and alcohols or amines. The reaction proceeds with retention of configuration with both chiral secondary alcohols and α-amino acid derivatives allowing access to useful chiral auxiliaries, ligands, and organocatalysts. Ester and amide products can be isolated directly in high yield due to the water soluble nature of the side products.

A salt made of 4-N,N-dimethylaminopyridine (DMAP) and saccharin as an efficient recyclable acylation catalyst: A new bridge between heterogeneous and homogeneous catalysis

Here, we report insights into the new recyclable catalyst 1, (DMAP·saccharin). The DMAP·saccharin-catalysed acylation of alcohols has been successfully carried out more than 8 times. Only 1 mol% of catalyst 1 efficiently promotes acylation with almost equimolar amounts of acid anhydrides, under both base-free and solvent-free conditions.

Widely useful DMAP-catalyzed esterification under auxiliary base- and solvent-free conditions

With regard to atom economy and E-factor, catalytic condensation of carboxylic acids with equimolar amounts of alcohols is the most desirable. Although several highly active dehydration catalysts have been reported, more efficient alternatives are still strongly needed because the dehydrative esterification of tertiary alcohols, phenols, acid-sensitive alcohols, amino acids, and hardly soluble alcohols has never proceeded satisfactorily. Here we report new insights into the classical DMAP-catalyzed acylation of alcohols: surprisingly, only a 0.05-2 mol % of DMAP can efficiently promote acylation of alcohols with acid anhydrides under auxiliary base- and solvent-free conditions to give the corresponding esters in high yields. Furthermore, we achieved the recovery and reuse of commercially available polystyrene-supported DMAP without using any solvents. These serendipitous findings provide widely useful and environmentally benign esterification methods, which might be more practical and reliable than catalytic dehydrative condensation methods, in particular, for the less reactive alcohols which hardly condense with carboxylic acid directly.