Convenient ketone synthesis via n-acylaziridines

N-Acylaziridines couple efficiently with organolithium and Grignard reagents to produce ketones in high yields.     

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 carbazoles via 2-vinylindoles.

2-Vinylindoles are obtained from the Fischer indolization of α,β-unsaturated ketones. Heating 2-(2-methylpropenyl)indole (4) with the Vilsmeier reagent (DMF/POCl₃) gave 2-methylcarbazole in good yield, presumably $\text{via}$ an electrocyclic ring closure of a hexatrienic intermediate.     

Epimerization of bicyclic vinyl tertiary-alcohols via [2,3] sigmatropic rearrangement

General methods for inverting the stereochemisty of vinyl $\text{tertiary}$-alcohols such as $\text{2}$ and $\text{5}$ into $\text{3}$ and $\text{8}$ respectively are described. The procedures employ a [2,3] sulfoxide rearrangement and will facilitate the extended use of the oxy-Cope rearrangement to a variety of related ring systems.     

Preparation of halo-F-methanes via potassium fluoride-halogen cleavage of halo-F-methylphosphonium salts

Treatment of halo-$\text{F}$-methylphosphonium salts with potassium fluoride and halogen (I₂, Br₂, ICl, IBr) gives modest yields of halo-$\text{F}$-methanes. This method of preparation augments the classical Hunsdiecker approach to these materials.     

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.     

Diastereoselective synthesis of N-acetyl-D,L-acosamine and N-benzoyl-D,L-ristosamine

N-Acyl derivatives of $\text{D}$,$\text{L}$-acosamine and $\text{D}$,$\text{L}$-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters.     

β-tributylstannylacrylates. Stereospecific synthesis via conjugate additon of tributylstaknylcopper

The synthesis of $\text{cis}$- and $\text{trans}$-8-tributylstannylacrylates from conjugate addition of tributylstannylcopper to various β-substituted acrylates is shown to be a highly stereospecific reaction. Of four tributylstannylmetal reagents examined for this conversion, optimum results were obtained with tributylstannylcopper.     

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 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.     

Preparation of gem-difluorocyclopropanes via decomposition of methyl chlorodifluoroacetate by alkali metal halides

The facile decomposition of methyl chlorodifluoroacetate, induced by either lithium chloride/hexamethylphosphoric triamide complex or potassium fluoride/18-Crown-6 complex, has been carried out in the presence of a variety of olefinic substrates to yield the corresponding $\text{gem}$-difluorocyclopropanes. The ester decomposition has been determined to yield “free” difluorocarbene $\text{via}$ a three-step process involving an intermediate chlorodifluoromethide ion.     

[2+2] Cycloaddition of benzyne to cis,trans- and cis,cis-1,5-cyclooctadiene

The relative rates of formation of $\text{cis}$ and $\text{trans}$ [2+2]cycloadducts of benzyne to $\text{cis}$, $\text{trans}$- and $\text{cis}$, $\text{cis}$-1,5-cyclooctadiene, $\text{trans}$- and $\text{cis}$-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.     

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.     

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.     

Synthesis of single isomers (E or Z) of unsaturated alcohols by the horner-wittig reaction

Single isomers ($\text{E}$ or $\text{Z}$) of homoallylic and higher alcohols can be synthesised from ω-hydroxyalkyldiphenylphosphine oxides and aldehydes, or from alkyldiphenylphosphine oxides and lactones