68366-66-5

Upstream product

• 2216-51-5 (-)-menthol 
• 221887-36-1 2,2,2-tribromoethyl cyclohexanecarboxylate 
• 98-89-5 Cyclohexanecarboxylic acid 
• 1127-08-8 cyclohexanedicarboxylic acid 
• 2719-27-9 cyclohexanylcarbonyl chloride 
• 35665-26-0 N-benzylcyclohexanecarboxamide 

Downstream Products

• 258265-83-7 1-Cyclohexyl-2-((R)-toluene-4-sulfinyl)-ethanone 
• 68326-61-4 1-Cyclohexyl-2-((S)-toluene-4-sulfinyl)-ethanone 
• 98-89-5 Cyclohexanecarboxylic acid 

Relevant academic research and scientific papers

Nickel-Catalyzed Esterification of Aliphatic Amides

Recent studies have demonstrated that amides can be used in nickel-catalyzed reactions that lead to cleavage of the amide C?N bond, with formation of a C?C or C?heteroatom bond. However, the general scope of these methodologies has been restricted to amides where the carbonyl is directly attached to an arene or heteroarene. We now report the nickel-catalyzed esterification of amides derived from aliphatic carboxylic acids. The transformation requires only a slight excess of the alcohol nucleophile and is tolerant of heterocycles, substrates with epimerizable stereocenters, and sterically congested coupling partners. Moreover, a series of amide competition experiments establish selectivity principles that will aid future synthetic design. These studies overcome a critical limitation of current Ni-catalyzed amide couplings and are expected to further stimulate the use of amides as synthetic building blocks in C?N bond cleavage processes.

One-pot decarboxylative acylation of N-, O-, S-nucleophiles and peptides with 2,2-disubstituted malonic acids

Monocarbonyl activation of 2,2-disubstituted malonic acids with benzotriazole leads to decarboxylation of one of the carboxy groups and formation of a C-H bond. Intermediate carbonyl benzotriazoles then readily acylate nucleophilic reagents and peptides resulting in libraries of conjugates and peptidomimetics.

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.

Direct transacylation of 2,2,2-trihaloethyl esters with amines and alcohols using phosphorus(III) reagents for reductive fragmentation and in situ activation

Amides and esters have been synthesized from 2,2,2-trihaloethyl esters in one pot using phosphorus(III) reagents as reductants, with resultant carboxylate activation as an acyloxyphosphonium intermediate, and in situ trapping by amine or alcohol nucleophiles. Secondary and tertiary amides were synthesized, including a dipeptide, in good yields using hexamethylphosphorous triamide, (Me2N)3P, as reducing agent. Optimal yields of esters derived from primary and secondary alcohols were obtained using tributylphosphine and DMAP. Tribromoethyl esters provided yields superior to those obtained with trichloroethyl esters.