Reaction Dess-Martin oxidation

Related reactions Dess-Martin oxidation, Jones oxidation, Ley oxidation, Oppenauer oxidation, PTitzner-Moffatt oxidation, Swern oxidation ... 

The first step of the total synthesis of 31 is the (7v )-proli nc-calal yzcd aldol reaction between 4 and 32, which gave the aldol adduct 33 with a good yield (69%) and nearly perfect stereocontrol (>96% de, >99% ee, Scheme 10). The same results were observed when the reaction was carried out on a 40-mmol scale yielding 5.22 g of 33 without a decrease of selectivity. The free hydroxyl group of 33 was quantitatively protected as MOM-ether. After hydrogenolytic debenzylation the aldehyde-ketone was obtained after Dess-Martin oxidation followed by a double Wittig reaction to provide the bisolefine 34 in 41% yield over 4 steps (Scheme 10). 

Popular oxidation reactions of peptide alcohols such as the Parikh-Doering or Dess-Martin in addition to older oxidation reactions such as Collins, pyridinium chlorochromate, or Swern oxidation afford racemization free productsJ9121415 37-39 Oxidations using pyridinium dichromate results in racemization and low yields of product.[l3 Oxidation reactions have also been utilized in semisynthetic pathways of peptide aldehydes (1) peptide aldehydes are obtained through the enzymatic acylation of a peptide ester to an amino alcohol with subsequent oxidation of the peptide alcohol to afford the aldehyde, and (2) peptide aldehydes can also be obtained by direct enzymatic oxidation of the peptide alcohol by alcohol de-hydrogenaseJ40 41 ... 

New approaches to the intramolecular Diels-Alder reaction continue to be introduced. Mathias Christmann, now at the TU Dortmund, showed (Angew. Chem. Int. Ed. 2008, 47, 1450) that a secondary amine organocatalyst converted the prochiral dialdehyde 19 into the hicycHc diene 20 with high de and ee. Martin G. Banwell of the Australian National University prepared Organic Lett. 2008,10,4465) the triene 21 in high ee by microbiological oxidation of iodobenzene. On warming, 21 was converted smoothly into 22, which was carried on in a formal synthesis of platencin. 

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