S)-(+)-2-(p-tolylsulfinyl)-2-buten-4-olide: an enantiomerically pure Michael acceptor for asymmetric synthesis of 3-substituted 4-butanolides. (—)-podorhizon.

A short, reliable, and practical synthesis of ($\text{S}$)-(+)-2-($\text{p}$-tolylsulfinyl)-2-buten-4-olide has been developed, and the utility of this Michael acceptor for highly enantiocontrolled synthesis of 3-substituted 4-butanolides has been demonstrated.     

A short synthesis of (s)-5-hydroxymethyl-(5h)-furan-2-one and derivatives from d-ribonolactone

We describe a short synthesis of ($\text{S}$)-5-hydroxymethyl-(5$\text{H}$-furan-2-one and some 5-O-derivatives, which are being used as key starting products for the synthesis of several antileukaemic lignan lactones, from $\text{D}$-ribonolactone.     

Stereospecific total synthesis of 12-(r)- and 12- (s)-forms of 6-trans leukotriene B

Non enzymatic hydration of leukotriene A ($\text{1}$), the biogenetic precursor of leukotriene B ($\text{2}$) affords among other products two diastereomeric 6-$\text{trans}$-isomers of 2, the first stereospecific and efficient syntheses of which are recorded herein.     

Aymmetric synthesis of (R) - and (S)-citramalate in high enantiomeric purity

An asymmetric synthesis of both isomers of dimethyl 2-acetoxycitramalate in over 96% enantiomeric excess is described.     

Palladium catalysed synthesis of N and S heterocyclic esters

Palladium catalysed alkoxycarbonylation of heterocyclic halides affords a simple and versatile synthesis of both $\text{N}$ and $\text{S}$ heterocyclic esters where a range of catalysts have been studied and a method to employ inexpensive inorganic bases has been found.     

Synthesis of the enantiomeric forms of cis and trans 1-benzyloxy-2,3-epoxy butane and of (3S,4S) 4-methyl-3-heptanol

The C₄erythro and threo diols (7) and (8) are converted either into the chiral epoxides (13) and (15) or into the enantiomers (14) and (16); the epoxide (13) is used as chiral synthon for the preparation of (3$\text{S}$,4$\text{S}$) 4-methyl-3-heptanol (21).     

Stereocontrolled (E,Z and erythro, threo) synthesis of ⊙-hydroxyallylic sulphides

All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.     

Synthesis of (1s,5r)-karahana ether and (1s,5r)-karahana lactone,the optically active forms of unique monoterpenes wit

(1$\text{S}$,5$\text{R}$)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabi-cyclo[ 3.2.1]octane) and (1$\text{S}$,5$\text{R}$)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo [3.2.1]octan-7-one) were synthesized from ($\text{S}$)-3-hydroxy-2,2-dimethylcyclo-hexanone. The natural karahana lactone was shown to be almost racemic ($\text{ca}$. 1.3 % e.e.).     

Stereoselective synthesis of (1R,3R,5S-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane

(1$\text{R}$,3$\text{R}$,5$\text{S}$)-1,3-Dimethyl]-2,9-dioxabicyclo[3.3.1]nonane $\text{1}$ has been stereoselectively synthesized based on a highly stereoselective method for the synthesis of 1,3-$\text{syn}$-polyol.     

The ipso-nitration of p-cresol

The nitration of $\text{p}$-cresol by nitric acid in aqueous sulphuric acid involves ~40% $\text{ipso}$-substitution at C^Me. The 4-methyl-4-nitrocyclohexa-2,5-dien-1-one (I) formed undergoes an acid-catalysed rearrangement to 4-methyl-2-nitrophenol.     

Autorecycling oxidation of alcohol catalyzed by 1,3,7,9,11,12,14-heptazapentacene-2,4,8,10 (14H,3H,9H,12H)-tetraones (mixed flavins)

1,3,7,9,11,12,14-Heptazapentacene-2,4,8,10 (14$\text{H}$,3$\text{H}$,9$\text{H}$,12$\text{H}$)-tetraones (mixed flavins) were prepared by the cyclization of 1,5-dihydro-8-[N-alkyl-N-(5-nitrouracil-6-yl)-amino-5-deazaflavins with Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral condition in sunlight and a remarkable autorecycling was observed.     

Stereoselective photosolvolyses of ipso-acetoxynitro-adducts of p-xylene

Diastereoisomers of 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl acetate exchanged acetoxyls for alkoxyls on irradiation in alcohols to give the diastereoisomers of alkyl, 1,4-dimethyl-4-nitro-2,5-cyclohexadienyl ethers in isomer ratios of 70:30, whereas the irradiation in pentane yielded $\text{p}$-xylene.     

A chiral intermediate for thienamycin analogue synthesis: (3S,4R)-4-(2-hydroxyethyl)-3-[(R)-1-(4-nitrobenzyloxycarbonyloxy)etryl]azetidin-2-one

Incorporation of a chiral ketone into the established tetrahydro-1,3-oxazine route to thienamycin analogues, has enabled the isolation of single enantiomers having the naturally occurring ($\text{R}$)-configuration at the bridgehead.     

A practical synthesis of (Z)-3-alkenoates

Deconjugative protonation of ($\text{E}$)-2-alkenoate with bulky alkoxy group using potassium disilazide as the base gives (Z)-3-alkenoate selectively.     

Methods for stereospecific synthesis of cis or trans hydrindanones

Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding $\text{trans}$ fused or $\text{cis}$ fused hydrindanone (1 or 2, respectively.)     

A stereocontrolled synthesis of Z and E terminal dienes from pinacol E-1-trimethylsilyl-1-propene-3-boronate

Pinacol $\text{E}$-1-trimethylsilyl-1-propene-3-boronate reacts with aldehydes to form (±)-($\text{R}$*,$\text{S}$*)-3-trimethylsilyl-4-hydroxy-1-alkenes, which can be deoxysilylated stereoselectively to either 98% $\text{Z}$ or 99% $\text{E}$ 1,3-dienes, including the separate components of the red bollworm moth pheromone.