1- Hydroxy-3,7-dimethyl-6-octen

Biochemisch werden Aldehyde i. a. zu den entsprechenden Alkoholen reduziert, wobei sie gelegentlich der mikrobiologischen Cannizzaro-Disproportionierung zu Carbonsaure und Alkohol unterliegen konnen [z. B. 3,7-Dimethyl-octen-(6)-al (Citronellal) zu 8-Hydroxy -2,6-dimethyl-octen-(2) und 3,7-Dimethyl-octen-(6)-sdure]1. 

Hydroxy-3,7-dimethyl-ocladien- 8-Hydroxy-2,6-dimethyl-octen-(2)... 

This oil also contains tagetonal, (+)-3,7-dimethyl-3-hydroxy-l-octen-5-onc. ... 

Oxo-4-[6-carboxy-hexen-(2)-yl]-3-[3-hydroxy-octen-(l)-yl]- 723 3-Oxo-2,4-dimethyl- 622 3-Oxo-1,5-diphenyl- 669... 

Compared to the anodic oxidation of Z-4-octene-l,8-diol (80%, Table 8) its oxidation with pyridinium dichromate in dimethyl formamide gave as the best chemical alternative only 65 % diacid Nickel peroxide oxidation under mild conditions (1.3 eq. peroxide, 25 °C, 1 M NaOH) led to 45% hydroxy acid 75, whereas under more vigorous conditions (3 eq. peroxide, 80 °C, 1 M NaOH) maleic acid was formed ... 

The epoxidation of dehydrolinalyl acetate 35 provides the corresponding epoxide 36 (75 %) which can lead to karahanaenone 38, a key odorous component of hop oil621. The epoxide 36 can be converted to the keto acetate 37 (82%) by an electrogenerated acid (EG Acid)-catalyzed rearrangement. Hydrogenation followed by alkaline hydrolysis of 37 gives 6-hydroxy-2,6-dimethyl-7-octen-3-one (86%) and subsequent thermal dehydration at 200 °C affords 38 (Scheme 3-12). 

IV/lc, 150 (Dien-Hydrier.) Vl/lb, 729 (Trennung) 3( )-Octen (S)-2.6-Dimethyl-2-hydroxy- E13/2, 1134 (Hydroxy-lierung + Allyl-Verschiebung) 4-Octen 4,7-Dimethyl-l-hydroxy-E21d, 3350 (]3.3]-sigmatr. Rearrangem.)... 

Figure 5.1a (Continued) octadiene-3,6-diol) (11) hydroxycitronellol (3,7-di methyloctane-l,7-diol) (12) 8-hydroxydihydrolinalool (2,6-dimethyl-7-octene-l,6-diol) (13) 7-hydroxygeraniol (E-3,6-dimethyl-2-octene-l,7-diol) (14) 7-hydro-xynerol (Z-3,6-dimethyl-2-octene-l, 7-diol) (15) cis and trans 8-hydroxy linalool (E- and Z-2,6-dimethyl-2,7-octadiene-l,6-diol) (16) p-menthenediol I (p-menth-l-ene-7,8-diol) (17) E-geranic acid (3,7-dimethyl-2,6-octadienoic acid) (18) E-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid (19) E- and Z-sobrerol or p-menthenediol II (p-menth-l-ene-6,8-diol) (20) cis and trans rose oxide (21) nerol oxide (22) 2-exo-hydroxy-1,8-cineol (23) 1,8-cineol (24) wine lactone (25) cis and trans 1,8-terpin (26) triol (2,6-dimethyloctane-2,3,6-triol) (27) hotrienol [(5E)-3,5-dimethylocta-l,5,7-trien-3-ol] (28) myrcenol (2-methyl-6-methylene-7-octen-2-ol)...

Hydroxy-isoehinolin + 1,1-Dimethyl-athylen 6g + 31 g 700 ml N,N- Dimethyl- auetamid 6 Tage 3-Oxo-9,9-dimethyl-(benzo-2-aza-bicyclo [d.2.0] octen-(4)) 46 144-147 2... 

The analogous situation for cyclohexyl systems undergoing Type I intramolecular ene reactions is exemplified by the cyclization of (.S )-3,7-dimethyl-6-octenal (citronellal) where mixtures are produced, in accord with expectations based upon the results of the reaction with methyl 3-[( )-3-benzoxy-l-propenyl]-6-oxohexanoate (see Table 5)101-102. However, a chiral zinc-based Lewis acid has been shown to effect this transformation with a high level of selectivity for the hydroxy group tram to the isopropylidene group (vide infra). 

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