1.7- Dioxaspiro-3-hydroxy undecane

In an analogous manner, benzodithiepins 286 can be lithiated with n-BuLi at —40 to —20 °C and reacted with alkyl bromides458 and with epifluorohydrin459. The enantiomers of l,7-dioxaspiro[5.5]undecane and 4-hydroxy-l,7-dioxaspiro[5.5]undecane, components... 

Ballini, R. and Petrini, M. 1992. Hydroxy-functionalized conjugated nitro olefins as immediate precursors of spiroketals. A new synthesis of l,7-dioxaspiro[5.5]undecane and ( )-2-methyl-l,7-dioxaspiro[5.6]dodecane. Journal of the Chemical Society, Perkin Transactions, l(23) 3159-60. 

Finally, oxidative cyclization (HgO, I2, hiA of tqjpropriately substituted alcoholic ethers formed the basis of Kay s stereoselective syntheses of both 4-hydroxy-l,7-dioxaspiro[S.S]undecane, an olive fly pheromone component, and ( )-talaromycin B (equations 4 and 5). More recently, Danishefsky et at have further extended the scope of this spiroketal-forming reactitm in their elegant total synthesis of avermectin Ai (equation 6). ... 

Spiroketals are also obtained in good yield starting from hydroxy enones, although diastereo-meric mixtures are generally recovered. Only 10-hydroxy-l-tetradecen-6-one (15) cyclizes with high stereoselectivity to give 2-butyl-8-methyl-l, 7-dioxaspiro[5.5]undecane (16) in 88 % yield as a 96 4 E,E)j E,Z) diastereomeric mixture102. The major diastcrcomer is separated by preparative GLC and identified on the basis of its H-NMR spectrum. 

However, 1-hydroxy-l-phenyl-9-decene-3,5-dione (19), upon selenium-mediated cyclization, affords (L, L )-2-phenyl-8-[(phenylseleno)methyl]-l,7-dixoaspiro[5.5]undecan-4-one (20) in 50% yield with total asymmetric induction. Subsequent Raney nickel reduction gives (E.JS J-S-methyl-2-phenyl-l,7-dioxaspiro[5.5]undecan-4-one (21) in 94% yield 105-106. 

Scheme 6 Conversion of iV -(4-Nitro-2,6-dioxaspiro[5.5]undecan-4-yl)methoxycarbonyl-Protected Lysine into the Ai -[3-Hydroxy-2-(hydroxymethyl)-2-nitropropoxycarbonyl] Derivative by Acid Cocktails Used in the Cleavage of tm-Butyl Alcohol Derived Protecting Groups, Followed by Cleavage of the Ai -[3-Hydroxy-2-(hydroxymethyl)-2-nitropropoxycarbonyl] Derivative Under Basic Conditions ...

Both enantiomers of 3-hydroxy-l,7-dioxaspiro[5.5]undecane (471), the minor component of the olive fly pheromone, can be synthesized from (5)-malic acid via acetonide 454b (Scheme 66) [120]. The initial carbon skeleton is constructed by sequential alkylation of 341 with 454b and then EE-protected 4-iodobutanol. Copper-mediated hydrolysis of the dithiepin ring affords a complex mixture of products, two of which, (3aS, 65)-471 and 472, are isolated in 33% and 18% yields respectively. 

Cyanuryi chioride. See Cyanuric chloride Cyasorb UV 9. See Benzophenone-3 Cyasorb UV 24. See Benzophenone-8 Cyasorb UV416. See 2-Hydroxy-4-acryioyioxyethoxy benzophenone Cyasorb UV 500. See 1,5-Dioxaspiro [5.5] undecane 3,3-dicarboxylic acid, bis (2,2,6,6-tetramethyi-4-piperidinyl) ester Cyasorb UV 531. See Benzophenone-12 Cyasorb UV 1084. See 2,2 -Thiobis (4-t-octylphenolato)-n-butylamine nickel Cyasorb UV 1164. See 2-[4,6-Bis (2,4-dimethylphenyl)-1,3,5-triazin-2-yl1-5-(octyloxy) phenol... 

Benzophenone-3 Bis [2-hydroxy-5-methyl-3-(benzotriazol-2-yl) phenyl] methane 1,5-Dioxaspiro [5.5] undecane 3,3-dicarboxylic acid, bis (2,2,6,6-tetramethyl-4-piperidinyl) ester 4-Dodecyloxy-2-hydroxybenzophenone Drometrizoie... 

Preparation of (4S,6S)-4-hydroxy-4,9-dioxaspiro[5.5] undecane (47), a pheromone component of the olive fruit fly. 

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