Syntheses Using Carbohydrates as Chiral Educts Chirons

3A Syntheses Using Carbohydrates as Chiral Educts ( Chirons ) 

A book by S. Hanessian (1983) discusses this subject in detail. We give one example herf and one in section 4.8.3. 

The synthesis of 11-oxaprostaglandlns from o-glucose uses the typical reactions of gl cofuranose diacetonide outlined on p. 267. Reduction of the hemiacetal group is achieved a thioacetal. The carbon chains are introduced by Wittig reactions on the aldehyde grou] which are liberated by periodate oxidation and laaone reduction (S. Hanessian, 1979 G Lourens, 1975). 

The partial or full structures given above indicate the following difnculties which one has to face in synthesis of pharmacologically interesting PGE and PGF derivatives  

We shall concentrate in our short account of PG syntheses on solutions to both problems as provided in the literature. Some fundamentals of cyclopentane synthesis have been discussed in section 1.13.3 (see also 4.5.1). 

Prostaglandins (= PG) constitute a class of hormones that are present in almost all human tissues and fluids in minute concentrations and are thought to play a dominant role in the control of pregnancy, hypertension, ulcers, asthma, and pain. Since they may be useful as pharmaceuticals, several total syntheses were developed, and the term to, prostaglandize a class of compounds, which means to exhaust its synthetic potentials, has become known. The principal structures of prostaglandins are shown below. The capital letters A,B,C,E,F denote the state of oxidation and the position of double bonds in the cyclopentane or cyclopentene ring the numeral subscript refers to the number of double bonds in the side-chains 1 = (trans)-13 2 (cis,trans)-6,13 3 = (cis,trans,cis)-6,13,17 a( = below) and fi( = above) indicate the position of the hydroxyl group on C-9. 

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