1.7- Dioxaspiro- -dodecane

Dioxaspiro[5,6]dodecane 11 was subjected to hydroformylation in the presence of RhHCO(TPP)3 using syngas to give 9-formyl-7,12-dioxaspiro[5,6]dodecane 118, which was transformed into dioxepanes 83 and 85 by standard procedures (Scheme 29) <2005SC971>. 

Two important spiroketals, such as l,7-dioxaspiro[5.6]undecane (29a), the major component of the olive fruit fly (Dacus oleae) sex pheromone (Baker et ah, 1980 Fanelli et ah, 1983), and ( )-2-methyl-l,7-dioxaspiro[5.6]dodecane (29b), a component of pheromone of Andrena haemorrhoa (Bergstroem et al., 1981 Katsurada and Mori, 1984), have been prepared in a cascade process from polyfunctionalized nitroalkanes (26) (Ballini and Petrini, 1992). 

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. 

Katsurada, M. and Mori, K. 1984. Pheromone synthesis. LXIV. Synthesis of the enantiomers of 2-methyl-l,7-dioxaspiro[5.6]dodecane, a component of the volatile secretion from the mandibular glands of Andrena haemorrhoa F. Liebig Annals of Chemistry, 1 157-61. 

In the synthesis of (S)-zearalenone and of a chiral spiroac-etal, (2S,6/ )-2-methyl-l,7-dioxaspiro[5.6]dodecane, the starting product was a functionalized 3-keto sulfoxide resulting from the reaction of glutaric anhydride with lithiated (+)-(7 )-methyl p-tolyl sulfoxide (eq 6). 

Thus, starting from ethyl (5)-p-hydroxybut5rrate, pheromones of diverse structural types, such as (5)-sulcatol [26], femilactone II [27], (25,6i )-2-methyl-l,7-dioxaspiro[5.6]-dodecane [28], (25,6/ ,S5)-2,8-dimethyl-l,7-dioxaspiro[5.5]undecane [29], (2R,5S)-2-methyl-5-hexanolide [31], and (2S,SjR)-8-methyl-2-decanol propanoate [32], have been synthesized. Methyl (5)-P-hydroxybutyrate has also been used for the synthesis of (25,35,75)-3,7-dimethylpentadecan-2-ol [33]. In these syntheses, the configurations at the... 

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