Barbara Achmatowicz

BF3-mediated reaction of a sulphone with aldehydes: A method for sterospecific construction of prostaglandin ω-chain

Abstract A new method for stereospecific construction of the allylic alcohol moiety of prostaglandins, based on application of optically active α-hydroxy aldehydes, is described. In the presence of BF3 .Et2O, lithiated sulphones 1 prepared from Corey aldehyde, and carbonyl compounds 2 give t or only their traces were formed. The addition products 3 , in the form of benzoates, mesylates or free alcohols, were subjected to reductive elimination by means of sodium amalgam to give the alkenes 4 . Compounds 4d and 4f were transformed into racemic and natural PGF2α, respectively, in line with the known method.

A novel approach to prostaglandins from the corey lactone involving BF3-mediated reactions of a sulphone and aldehydes

Abstract Transformation of the diol 1 via epimeric sulphones 7 to PGF 2α , is described. Alkylation of lithiated sulphones 7 with aldehydes 8a, 8b or 8c in the presence of BF 3 efficiently gives corresponding adducts.

Enantioselective synthesis of the methylenecyclopropane derivative related to hypoglycine, from malic acid

Abstract Synthesis of (S)-methylenecyclopropaneacetic acid starting from L-(−)-malic acid, via (2S)-O-tert-butyldimethylsilyl-1,2-epoxybutan-4-ol and 1-O-tert-butyldiphenylsilyl-5-benzenesulfonyl-6-trimethylsilylhexane-1,3-diols as the key intermediates, is described.

Transformations of tartaric acid: A facile synthesis of derivatives of optically active α-hydrohyaldehydes

Abstract Methods for synthesis of ( R )-and ( S )-2-benzyloxy- and 2-(t-butyldiphenylsilyloxy)-aldehydes from optically active tartaric acids are described.

Enantioselective syntheses of a 1α-hydroxyvitamin D ring A precursor from 3-(triphenylsilyl)glycidol and from malic acid

Abstract Syntheses of the 1α-hydroxyvitamin D 3 A ring fragment 2 from (2 R ,3 R ) 3-(triphenylsilyl)glycidol 5a and from L-(−)-malic acid are described.

The first synthesis and biological testing of the enantiomer of 1α,25-dihydroxyvitamin D 3

Abstract The 1α,25-dihydroxyvitamin D 3 enantiomer was synthesized and examined in biological tests. The ring A precursor was prepared from vitamin D 2 employing the Mitsunobu reaction for inversion of the configuration at C-3 and SeO 2 hydroxylation at C-1. The CD rings-side chain portion was synthesized from an optically active hexanoic acid derivative using diastereoselective tandem Mukaiyama–Michael addition and vinylsulfone reduction as the key steps. The ring A and CD rings building blocks were combined using the Julia alkenylation reaction. 1α,25-Dihydroxyvitamin D 3 enantiomer shows no significant affinity to the vitamin D receptor.

Iterative syn-1,3,5-triol synthesis utilizing the reaction of β-(trimethylsily)dalkyl phenyl sulphones with oxiranes

Abstract Partly protected triols 8a and 8b were synthesised from epoxide 1 using β-trimethylsilyl sulphones 2a and 2a for the chain elongation and the Cardillo procedure for diastereoselective two-step epoxidation of homoallylic alcohols.

Migration of aryl groups from silicon to carbon in α,β-epoxysilanes. A new model for hypervalent silicon study

Abstract The reaction of (2 R ,3 R )-3-(triphenylsilyl)glycidol ( 1 ) with n -Bu 4 NF·3H 2 O in THF, followed by treatment of the product with p -nitrobenzoyl chloride yields (2 S )-glycidol p -nitrobenzoate ( 4 ) and trans -cinnamyl p -nitrobenzoate ( 6 ) in a ratio of 1:1.5. The reaction of ( R )Si-( 2R,3R )- or ( R )Si-( 2S, 3 S )-3-[(methyl)(phenyl)(1-naphthyl)silyl]-glycidols, 7 or 8 respectively, with n -Bu 4 NF·3H 2 O affords mixtures of the respective glycidol, trans -cinnamyl alcohol and 3-(1-naphthyl)allyl alcohol. No significant difference in the product distribution in reaction of these two diasteromers was observed.

A method for the construction of the prostaglandin side chain based on addition of a sulphone and an oxirane

Unsaturated ketones (7) were obtained in a reaction sequence involving BF3-mediated addition of the alkylaryl sulphone (3) and oxiranes (4), oxidation of the hydroxy group in the adducts, and elimination of arylsulphinic acid; the C-6 functionalization had a long-range effect on the steric course of reduction of the 15-oxo group in prostaglandin intermediates.

Synthesis of the glycidol (1R,2R)-1-iodo-2-(triphenylsilyloxy)cyclopropane: new rearrangements of 2,3-epoxy-3-(trialkyl/arylsilyl)-propan-1-ols

Reaction of the mesylates of selected glycidols 1b, 5a, 5b and 5c with sodium iodide in acetone has been investigated. The mesylate 1b afforded the iodide 2 and the cyclopropane derivative 3 in a ratio which depended upon the reaction time. Whilst the mesylate 5a provided the iodide 6a as the sole product, the mesylates 5b and 5c gave mixtures of the corresponding unrearranged iodoepoxysilanes 6b and 6c, and the epoxides 7b and 7c.