Pfitzner-Moffat

The Oxidation of Some Carbohydrate Derivatives using Acetic Anhydride - Methyl Sulphoxide Mixtures and the Pfitzner-Moffat Reagent. Facile Synthesis of 3-Acetamido-3-deoxy-D-glucose and 3-Amino-3-deoxy-D-xylose, J. S. Brimacombe, J. G. H. Bryan, A. Husain, M. Stacey, and M. S. 

The synthesis of latanoprost (1) commences with the lactone 5 derived from the Corey lactone (Scheme I).11 12 The early introduction of the p-phenylbenzoyl protecting group12 in this lactone affords crystalline intermediates in the synthesis that are easy to handle and purify. In the next step, the primary alcohol functionality in the lactone 5 was oxidized using Pfitzner-Moffat conditions (DCC, DMSO and phosphoric acid) to yield the aldehyde 6. The crude aldehyde was then treated with dimethyl (2-oxo-4-phenyl)-phosphonate under Wadsworth-Emmons conditions (NaH, DME) to afford the enone 7 as a white crystalline solid in 59% yield. 

The same intermediate 74 was synthesized by J. W. Bruin et al74 by an alternative route. They reduced the ester function of the pyroglutamate with LiBH4 to the primary alcohol 75a which was protected as the acetate 75b to prevent O-alkylation. Reaction of the sodium salt of 75 b formed with NaH in dimethylformamide, with methyl-7-bromoheptanoate followed by methanolysis of the acetate function gave 74. Oxydation of the alcohol 74 by Pfitzner-Moffat-oxydation or oxydation with Collins reagent led to the unstable aldehyde 77. 

Peptide analysis Cyanogen bromide. 2,4-Di-nitrofluorobenzene. Diphenylphosphoroisothiocyanidate. Ethylene chlorophosphite. Hydrazine sulfate, lodoacetamide. Pfitzner-Moffat reagent. 

Oxidation of alcohols to aldehydes or ketone by DMSO activated with DCC (Pfitzner-Moffat), Ac2Q, (COCI)2, TFA, (Swem), P205l or pyridine-S03 (see 1sted). 

The oxidation of alcohols to carbonyl compounds is one of the most fundamental and important processes in the fine chemical industry. The classical methodology is based on the stoichiometric use of heavy metals, notably Cr and Mn (1,2). Alternatively metal-free oxidation, such as the Swern and Pfitzner-Moffat protocols, is based on e.g., dimethylsulfoxide as oxidant in the presence of an activating reagent such as N,N -dicyclohexylcarbodiimide, an acid anhydride or acid halide (3). Although the latter methods avoid the use of heavy metals, they usually involve moisture-sensitive oxidants and environmentally undesirable reaction media, such as chlorinated solvents. The desired oxidation of alcohols only requires the formal transfer of two hydrogen atoms, and therefore the atom economy of these methods is extremely disadvantageous. The current state of the art in alcohol oxidations... 

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