Acylation of alcohols and amines

Acids Nucleophile Activation Presence of other functional groups Reference 

3-nitro-5-trifluoromethyl benzoic acid ammonia, primary aliphatic amines, aliphatic alcohols acid chloride diethylphosphono [55] 

2-chloro-4-trifluoro-methyl-pyrimidine-5-carboxylic acid 3-amino-5-trifluoro methyl-benzoic amides and esters acid chloridec diethylphosphono [55] 

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Gotor-Fernandez, V., ReboDedo, F. and Gotor, V. (2007) Preparation of chiral pharmaceuticals through enzymatic acylation of alcohols and amines, in Biocatalysis in the Pharmaceutical and Biotechnology Industry, (ed. R.M. Patel), Dekker, Taylor and Francis, New York, Chapter 7, pp. 203-248. 

Although in recent years transesterification processes of racemic alcohols have received major attention, enzymatic acylation of amines for synthetic purposes is also being employed as a conventional tool for the synthesis of chiral amines and amides [31], using CALB as the biocatalyst in the majority of these reactions [31a]. The main difference between enzymatic acylation of alcohols and amines is the use of the corresponding acyl donor, because activated esters which are of utility... 

The seminal work of Klibanov in the early 1980s [46,47] made it clear that enzymes can be used in hydrophobic organic solvents, although at the price of a severely reduced reaction rate [48, 49]. Indeed, many Upases, as well as some proteases and acylases, are so stable that they maintain their activity even in anhydrous organic solvents. This forms the basis for their successful application in non-hydrolytic reactions, such as the (enantioselective) acylation of alcohols and amines, which now are major industrial applications [50]. 

Trichloromethyl-l,2-oxathietane 2,2-dioxide is a catalyst for the acylation of alcohols and amines under mild conditions.It also catalyzes the polymerization of (NPCl2)3. It is suggested that six-membered cyclic sultones are derived from /3-sultones transiently formed in the addition of sulfur trioxide to alkenes. Ring-expansion of 3,4,4-trifluoro-3-trifluorovinyl-l, 2-oxathietane 1-oxide occurs at 100°C to give 4,4,5,6,7,7-hexafluoro-l,3-dioxa-2-thiacyclohept-5-Halogenation of 3,3,4,4-tetrafluoro-l,2-oxathietane 2,2-dioxide in... 

Indium triiodide catalyzes transesterification processes, e.g. the acylation of alcohols or amines and the conversion of THP ethers to acetates (Scheme 8.143) [187]. Indium triflate is also an efficient catalyst for the acylation of alcohols and amines (Scheme 8.144) [188]. Carboxylates are hydrolyzed to the corresponding carboxylic acids in high yield by microwave-assisted reaction on the surface of moistened silica gel in the presence of indium triiodide (Scheme 8.145) [189]. 

With pyridine, acid chlorides and acid anhydrides yield A-acyl pyridinium salts 6 which are very reactive and sensitive to hydrolysis, unlike the quaternary salts 2-5 they are involved in the acylation of alcohols and amines in pyridine as solvent (Einhorn variant of the Schotten-Baumann reaction). However, 4-dimethylaminopyridine 12 (Steglich reagent) and 4-(pyrrolidin-l-yl)pyridine 13 are better acylation catalysts by a factor of 10 [46a]. Reactions with sulfonyl chlorides in pyridine proceed via A-sulfonylpyridinium salts 14. 

Lipases are knovm for their tolerance of hydrophobic media and are now widely used, also on an industrial scale [25], e.g., for enantioselective (de)acylations of alcohols and amines. Hence, it is not surprising that the most explored enzymes in I Ls are lipases. 

Pd nanoparticles supported on PANI-NFs are efficient semi-heterogeneous catalysts for Suzuki coupling between aryl chlorides and phenylboronic acid, the homocoupling of deactivated aryl chlorides, and for phenol formation from aryl halides and potassium hydroxide in water and air [493], PANl-NF-supported FeCl3 as an efficient and reusable heterogeneous catalyst for the acylation of alcohols and amines with acetic acid has been presented [494]. Vanadate-doped PANI-NFs and PANI-NTs have proven to be excellent catalysts for selective oxidation of arylalkylsulfides to sulfoxides under nuld conditions [412]. Heterogeneous Mo catalysts for the efficient epoxidation of olefins with ferf-butylhydroperoxide were successfully synthesized using sea urchin-Uke PANI hollow microspheres, constructed with oriented PANI-NF arrays, as support [495]. Pt- and Ru-based electrocatalyst PANI-NFs—PSSA—Ru—Pt, synthesized by the electrodeposition of Pt and Ru particles into the nanofibrous network of PANI-PSSA, exhibited an excellent electrocatalytic performance for methanol oxidation [496]. A Pt electrode modified by PANI-NFs made the electrocatalytic oxidation reaction of methanol more complete [497]. Synthesis of a nanoelectrocatalyst based on PANI-NF-supported... 

P. R. Likhar, R. Arundhathi, S. Ghosh, and M. L. Kantam, Polyanihne nanofiber supported FeCl3 An efficient and reusable heterogeneous catalyst for the acylation of alcohols and amines with acetic acid, J. Mol. Catal. A Chem., 302, 142-149 (2009). 

This reaction was first reported by Schotten in 1884 and subsequently extended by Baumann in 1886. It is the acylation of alcohols and amines from acyl halide or anhydride in an aqueous alkaline solution (e.g., 1 M NaOH), and is generally known as the Schotten-Baumann reaction or Schotten-Baumann acylation. Occasionally, it is also referred to as the Schotten-Baumann method,or Schotten-Baumann esterification. Likewise, the formation of benzoyl ester under these conditions is called the Schotten-Baumann benzoylation." It is assumed that the reaction would perform well if carried out in a biphasic system of water and an immiscible organic solvent (e.g., CH2CI2), which has an important application in the acylation of amino acids.For example, p-nitrohippuric acid and dibenzoylornithine (ornithuric acid) all can be prepared under these conditions. 

Enantioselective Acylation of Alcohol and Amine Reactions In Organic Syitthesis... 

ENANTIOSELECTIVE ACYLATION OF ALCOHOL AND AMINE REACTIONS IN ORGANIC SYNTHESIS... 

Serine Hydrolase Mechanism for the Acylation of Alcohols and Amines... 

Hydrolases possess a common feature for its mechanistic action. Their active site is built around three key amino acid residues, which are histidine (His), serine (Ser), and aspartic acid (Asp) or alternatively glutamic acid (Glu). This site, namely, the catalytic triad, forms a charge-relay network to polarize and activate the nucleophile, allowing the serine hydrolase mechanism to start [19]. This review covers the acylation of alcohols and amines using mainly esters so Figure 9.1 depicts the mechanism for these types of reactions is depicted. 

The enantioselective acylation of alcohols, and amine reactions by lipases and esterases in organic synthesis with examples of classical and dynamic kinetic resolutions of racemates, are shown, giving attention to the desymmetrization of meso-compoxmds. 

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