Solavetivone

The spiroketone (347), previously used as an intermediate in the synthesis of several vetispirane sesquiterpenoids (cf. Vol. 5, p. 79) has been converted into ( )-solavetivone (337) by the sequence of reactions shown in Scheme 31. ... 

Yao M.K. Desilets H., Charles M.T., Boulanger R. Tweddell R.J. Effect of mycorrhization on the accumulation of rishitin and solavetivone in potato plantlets challenged with Rhizoctonia solani. Mycorrhiza 2003 13 333-336. 

Bicyclic sesquiterpenes include a variety of bioactive compounds including the Solanaceae phytoalexins capsidiol (G61G6) from Capsicum frutescms (pepper) and the Solanum tuberosum (potato) antifungals rishitin (G61C6) and solavetivone (G6-G5) the Ipomoea batatus... 

Solavetivone (661) has also been a synthetic objective with two new syntheses having been completed. The first of these (Scheme 63) achieved syntheses of both solavetivone (661) and the hydroxy derivative (675), whose glucoside has been identified in tobacco.302 The second synthesis (Scheme 64) relied upon a Diels-Alder reaction to construct a bicyclo[2,2,2]octyl framework which was then cleaved by acid to release a prenyl-mesylate (679) for further acid-promoted... 

The reaction of trimethylaluminum [65,66] with cyclohexadienone was also catalyzed by the combination of the oxazoline ligand 28 and copper(I) triflate to afford relatively high selectivity (Scheme 15) [67]. The process was successfully applied to the asymmetric total synthesis of (-)-solavetivone [68]. 

Thus it has been shown that addition of sodium [ C2]acetate to potato tuber slices, which have been inoculated with Monilinia fructicola or Glomeralla cingulata, provides rishitin (549), lubimin (550), hydroxylubimin (551), 15-dihydrolubimin (552), solavetivone (553), isolubimin (554), 10-epilubimin (555),... 

Fujimori, T., R. Kasuga, H. Kaneko, and M. Noguchi Isolation of solavetivone from Nicotiana tabacimr. Phytochemistry 16 (1977) 392. 

A synthetically useful example of this process is the conversion of 117 to 120, which involves a 1,2-alkyl shift, and was part of Hwu s synthesis of (-)-solavetivone. 38 jhe alkyl fragment is actually part of the bicyclic ling system, one arm of the bicyclo[4.4.0]decane ring system. Reaction of the OH unit with the Lewis acid resulted in formation of the tertiary cation 118, which was followed by a 1,2-alkyls shift to give 119, where the new cation is stabilized by the adjacent silicon of the trimethylsilyl group. 39 Loss of the trimethylsilyl group from 119 gives spiran (120). 

In a continuing investigation of sesquiterpenoid stress compounds from Nicotiana species it has been shown that phytuberin (566) and phytuberol (567) are produced on treatment of N. tabacum with the ethylene-releasing substance ethrel (2-chloroethylphosphonic acid). Phytuberol is also generated on inoculation of N. rustica with tobacco mosaic virus (TMV), and solavetivone (568)... 

Fig. 2. Biosynthesis of some sesquiterpene phytoalexins. Phytub rin, solavetivone, lubimin, hydroxylu-bimin and rishitin are produced by Phytophthora-iniected potatoes (Soianum tuberosum) and by potato tuber disks treated with Elicitor (see). Capsidiol is a phytoalexin from Capsicum, [P.A.Brindle D.R.Threlfall Biochem. Society Transactions ft (1983) 516-522]...

Lycium. Solavetivone (Fig. 7.5) and (-)-l,2-dehydro-a-cyperone (Fig. 7.4), were identified as constituents of the volatile components from the half-dried berries of Lycium chinense (Sannai et al. 1982). 

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