74821-35-5Relevant articles and documents
Total Synthesis of (+/-)-Prostaglandin E2 Methyl Ester from exo-2-Bromo-endo-3-hydroxybicycloheptan-6-one using Dimethyl-t-butylsilyl Protected Intermediates
Howard, Colin,Newton, Roger F.,Reynolds, Derek P.,Roberts, Stanley M.
, p. 2049 - 2054 (2007/10/02)
Peracetic acid oxidation at -78 deg C of the dihydroxybicyclohepten-6-one (23) afforded the dihydroxylactone (24) which was protected as its bisdimethyl-t-butylsilyl ether (26) and reduced to the corresponding lactol (27).A Wittig reaction on (27), carried out in benzene with a short reaction time, gave mainly the required 11α-silyl ether (28) together with a trace of the 9α-silyl ether (29) which results from 1,5-migration of the silyl group.Oxidation of (28) followed by quantitative deprotection using aqueous HF in acetonitrile afforded (+/-)-PGE2 methyl ester (20).This short stereo- and regioselective total synthesis proceeds in an overall yield of 10percent starting from cyclopentadiene.
Total Synthesis of Prostaglandin-F2α involving Stereocontrolled and Photo-induced Reactions of Bicycloheptanones
Howard, Colin C.,Newton, Roger F.,Reynolds, Derek P.,Wardsworth, Alan H.,Kelly, David R.,Roberts, Stanley M.
, p. 852 - 857 (2007/10/02)
A short total synthesis of prostaglandin-F2α from cyclopentadiene is described.Acetalisation of bicyclohept-2-en-6-one (1) followed by formation of a singal bromohydrin gave on treatment with base the epoxyacetal (4).Reaction of (4) with the appropriate organocuprate reagent introduced both the 12β side-chain and 11α-hydroxy-group of the embryonic prostaglandin.The fused cyclobutane ring is important as it controls both the stereoselectivity of epoxide formation and the regioselectivity of the subsequent ring-opening reaction.Furthermore, the unusual photochemical behaviour of cyclobutanones was exploited in this synthesis.Irradiation of the bicycloheptan-6-one (9) in aqueous solution and subsequent Wittig olefination afforded prostaglandin-F2α.Baeyer-Villiger oxidation of the same ketone (9) furnished the lactone (16), a known precursor of prostaglandin-E.
