Total synthesis of prostaglandins. VII. Symmetric total synthesis of (-)-prostaglandin E1 and (-)-prostaglandin E2

Hydroxylation of prostanoids by fungi. Synthesis of (−)-15-deoxy-19-(R)-hydroxy-PGE1 and (−)-15-deoxy-18-(S)-hydroxy-PGE1

“…Product 10 is tentatively assigned the 3(S) configuration on the basis of a comparison of its optical rotation (-ve) with those of 6 (+ve) and the oxidation product of 9 (-ve), it having been shown that the configuration of substituent allylic hydroxyl groups on the alkyl chain of molecules such as 10 does not influence the overall sign of rotation of the molecule at longer wavelengths (7,23,24). The observation that the predominant configuration of 9 is different from that of 6, from which it is presumably derived, is not exceptional: the enantiomeric excess of 6 is not high, and an enzyme converting 6 to 9 need not operate with the same enantioselectivity at C-3 as one that produces 6, the enzymic functions of carbonyl reduction (by alcohol dehydrogenases) and hydroxylation (by mono-oxygenases) being unrelated.…”

“…The I3C nmr analysis of the ketals so obtained was used to determine the ee values given in Table 1. Product 28 was also assigned the 2(R),3(R) absolute configuration and an approximate ee of 20% based on the published negative rotation value of the corresponding C-7"-deoxy compound (7).…”

“…Although biotransformation of the natural prostanoids has been studied (5), and enzymic reactions such as ester hydrolysis (6), carbonyl/alcohol reduction/oxidation (7), and toluene dioxygenation (8) have been used to produce chiral prostaglandin synthons, the use of fungal biotransformation to enantioselectively hydroxylate simple racemic prostanoid precursors has not been reported by others.…”

Microbiological Systems in Organic Synthesis: Preparative-Scale Resolution of ( R S )-Glaucine by Fusarium solani and Stereospecific Oxidation of ( R )-(−)-Glaucine by Aspergillus flavipes

“…As a consequence of the early work of Prelog (16) and MacLeod et al (11), it may be suggested that organisms can often be classified as R or S, depending on the chiral specificity with a given type reaction on a restricted group of substrates. For example, Sih and co-workers (18,19) have described microbial systems for the stereoselective reduction of 2-substituted cyclopentane-1,3,4-triones as prostaglandin precursors. Thus, Mucor rammanianus demonstrates reduction of the 4-ketone to give the optically pure (4S)alcohol, whereas Dipodascus uninucleatus yields the corresponding (4R)-alcohol.…”

Synthesis of 3,5-dichlorocyclopentane-1,2,4-trione

“…Although parent completely enolized trione IIa has long been known [3][4][5], published data on its reactions are relatively poor. Known examples include only some simplest transformations of trione IIa, such as reactions with amines, diazomethane, methanol under acidic conditions, and dimethyl sulfoxide [6], as well as prostaglandin syntheses starting from substituted cyclopentanetriones [7,8]. According to [4,5], cyclopentanetrione IIa can exist as enol tautomers IIb and IIc (Scheme 1).…”