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• 75-21-8 oxirane 
• 13483-31-3 Acetone dimethylhydrazone 
• 80952-60-9 3-(Tetrahydropyran-2'-yloxy)butyliodide 
• 131990-57-3 N,N-Dimethyl-N'-[1-methyl-5-trimethylsilanyloxy-hex-(Z)-ylidene]-hydrazine 
• 133812-42-7 2-(4-hydroxypentyl)-2-(3-hydroxypropyl)-1,3-dithiane 
• 676998-90-6 2-(1-ethoxyethoxy)ethyl iodide 
• 89455-88-9 5-[Dihydro-furan-(2E)-ylidene]-pentan-2-ol 
• 79011-53-3 Methyl-7 dioxa-1,6 spiro<4.5>decanone-4 (E) 
• 74-88-4 methyl iodide 
• 616240-02-9 8-benzyloxy-1-hydroxy-non-5-yn-4-one 
• 126398-47-8 1-nitrohexan-5-one 
• 64584-96-9 2-[(5-bromopentan-2-yl)oxy]tetrahydro-2H-pyran 
• 142591-58-0 (5'S)-2-(1'-Oxo-5'-tetrahydropyranyloxyhexyl)butan-4-olide 
• 517-23-7 3-acetyl-2-oxo-4,5-dihydrofuran 

Relevant academic research and scientific papers

A convenient access to thermodynamically nonstabilised spiroketal isomers: The first synthesis of (Z)-7-methyl-1,6-dioxaspiro[4.5]decane

Functionalised hydroxy α-alkynones were transformed to the corresponding spiroketals by a one-pot cascade consisting of palladium-catalysed hydrogenation of the triple bond, hydroxyl group deprotection and spirocyclisation under mild nonacidic conditions. The reaction does not rely upon thermodynamic control to set the configuration of the ketal stereocentre so that both the anomerically stabilised and nonstabilised isomers are similarly accessible.

Alkynyltrifluoroborates as versatile tools in organic synthesis: A new route to spiroketals

(Chemical Equation Presented) A simple and efficient two-step approach to spiroketals is described. Key steps include the preparation of functionalized hydroxyl α-alkynones by ring-opening reactions of lactones with lithium alkynyltrifluoroborates followed by a palladium-catalyzed hydrogenation/ spirocyclization of the prespiroketal intermediate.

Lipase mediated resolution of 1,3-butanediol derivatives: Chiral building blocks for pheromone enantiosynthesis. Part 3

(R,S)-1,3-Butanediol 5 was kinetically resolved by enzymatic acetylation with vinyl acetate under the presence of Chirazyme L-2, c-f, yielding (S)-1-O-acetyl-1,3-hydroxybutane 6 and (R)-1,3-di-O-acetyl-1,3-butanediol 7 with enantiomeric excesses of 91% (E = 67.3). Compounds 6 and 7 were easily transformed into the corresponding (S)-3-O-(2-methoxyethoxymethyl)-3-hydroxybutanal 10 and (R)-3-benzyloxybutanal 19, through a protection-deprotection and functional group interchange methodology. Subsequent reaction of 10 and 19 with 3-(methoxycarbonylpropionylmethylene)triphenylphosphorane afforded methyl (E,S)-8-O-(2-methoxyethoxymethyl)-4-oxo-5-nonenoate 12 and (E,R)-8-benzyloxy-4-oxo-5-nonenoate 20. The alkenes 19 and 20 were then catalytically hydrogenated to the corresponding saturated esters 13 and 21. Treatment of 13 and 21 with 1,2-ethanedithiol/F3B·OEt2 afforded dithioketals 14 and 22, which were respectively reduced to (S)-1,8-dihydroxy-4-nonanone ethylidenedithioketal 15 and (R)-8-O-benzyl-1,8-dihydroxy-4-nonanone ethylidenedithioketal 23. Finally, deprotection of 15 by catalytic hydrogenation under acidic conditions gave the expected (5S,7S)-(-)-7-methyl-1,6-dioxaspiro[4.5]decane 1. The (5R,7R)-(+)-1 enantiomer was analogously prepared from 23. Both compounds were formed by this procedure with an e.e. of 91%.

Spiroacetals and other venom constituents as potential wasp attractants

The major volatile spiroacetals from the venom of both the common wasp, Vespula vulgaris and the German wasp V. germanica, viz. 7-methyl-1,6-dioxaspiro[4,5]decane and 7-ethyl-2-methyl-1,6-dioxaspiro[4,5]decane, respectively, were synthesized by known methods. These acetals, along with N-isopentylacetamide (the major volatile amide from wasp venom), 2-heptanone (a honeybee pheromone), 2-methyl-3-buten-2-ol (a component of hornet venom), cuticle wax from V. vulgaris, and venom sacs from both wasp species were assayed by EAG and olfactory bioassay for attractancy to V. vulgaris workers. Antennal responses to all test chemicals were recorded. Acetal isomers (±)-2 and (±)-3,N-isopentylacetamide, and 2-heptanone were attractive to V. vulgaris workers at levels of 1 μmol. Greater quantities of the same compounds were repellent to V. vulgaris workers.

Chemistry of Fruit-flies. Spiroacetal-rich Secretions in several Bactrocera species from the South-West Pacific Region

The male rectal glandular secretions from the fruit-fly pest species Bactrocera (Notodacus) xanthodes (Broun) and Bactrocera (Bactrocera) kirki (Froggatt) and the non-pest species, Bactrocera (Bactrocera) kraussi (Hardy) are rich in spiroacetals.In B. xanthodes, (5R,7S)-7-methyl-1,6-dioxaspiordecane is prominent, whereas in B. kirki (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiroundecane is the single major volatile component.B. kraussi, although rich (ca. 40percent) in (2S,6R,8S)-2,8-dimethyl-1,7-dioxaspiroundecane, contains other spiroacetals and a number of compounds that may be biosynthetically related to the spiroacetals.The ab- solute configurations have been determined by enantioselective syntheses and chiral gas-chromatographic determinations.The results of examinations of Bactrocera (Bactrocera) passiflorae (Froggatt) and Bactrocera (Bactrocera) facialis (Coquillett) are also reported.

CHEMICO-ENZYMATIC SYNTHESES OF RACEMIC AND CHIRAL ISOMERS OF 7-METHYL-1,6-DIOXASPIRODECANE

Porcine pancreatic lipase (PPL) mediated resolution of 6-heptene-2-ol afforded the enantiomers in high optical purities.Alkylation products of the dianion of the 2-4'-hydroxypentyl-1,3-dithiane prepared from the enantiomers, followed by alkylative hydrolysis, afforded 97percent optically pure E-7-methyl-1,6-dioxaspirodecane.

Synthesis of spiroacetal pheromones via metalated hydrazones

The synthesis of simple alkyl substituted spiroacetals by α,α'-alkylation of metalated acetone dimethylhydrazone with appropriate electrophiles and subsequent acid catalyzed cleavage and ring closure of the products is described.

FUNCTIONALIZED NITROALKANES IN SYNTHESIS OF 1,6-DIOXASPIRO(4.5)DECANE COMPONENTS OF PARAVESPULA VULGARIS PHEROMONE

(E)-2-, (Z)-2-, and (E)-7-methyl-1,6-dioxa(4.5)decane isomers which are components of odours of Papavespula vulgaris have been prepared by two practical and efficient procedures starting from easily available functionalized nitroalkanes.