Monic acid synthesis

White and coworkers used trans Addition of bromine and (-)-l-bomeol to 3,4-dihydro-2//-pyran to afford the stereoisomeric bomyl bromotetrahydropyranyl ethers (3) and (4 Scheme 44) which are employed in an enantioselective total synthesis of (-)-monic acid C (Scheme 5).10 A simple synthesis of 4-methylthio-l,2-dithiolane, the photosynthesis inhibitor of the green alga Chara globularis (Scheme 45),83 exploits the observation that allylic sulfides undergo rearrangement on addition of bromine.84 Block and Naganathan employed the trans addition of bromine to 4-thioacetoxycyclopentene as a key... 

Recently, the protected tuberonic acid was synthesized by using the method shown in Scheme 10 and deprotection was studied with success to afford tuberonic acid for the first time (Scheme 13)846 Through the synthesis it was revealed that tuberonic acid and its derivative are liable to epimerization more easily than epi-jasmonic acid. In addition, exposure of tuberonic acid to NaOH in aqueous MeOH produced 12-hydroxyjas-monic acid. 

Synthesis of (-l-)-Pseudomonic Acid C. A total synthesis of (-l-)-pseudo-monic acid C employes an n-lkoSnH-mediated reductive elimination of the methyl xanthate derivative of a (5-hydroxy sulfone as one of the key steps (Eq. 160)."... 

The synthesis of several natural reduced pyrans or fragments of these molecules has received much attention. The conversion of the protected monic acid A (9 R=0C02Bu) into the ketone (9 R=Bu) has been effected with butylmanganese chloride,27 and this is important in the study of pseudomonic acid A.28 The dihydropyran (10), a key intermediate in the synthesis of this natural acid, has been synthesized from the lactone (11) by reaction with dimethyl sodio-malonate and Pd( PPh3 ) , 29... 

Activity Via the gas phase [ 10 nL ( )-( 1 )/L] it is a potent inducer of proteinase-inhibitor proteins in some species of Solanaceae and Fabaceae . After uptake in the cells it is presumably rapidly hydrolysed to jas-monic acid [C,2H,g03, Mr 210.27, viscous oil, bp. 125 °C (0.13 Pa)], a ubiquitous, intracellular, plant signal substance which stimulates the synthesis of special proteins and induces the plant s defensive reaction via a gene activation . De novo synthesis of (3/f,75)-(-t)-jasmonic acid and an increase in the intracellular concentration of (3/f,75)-(-F)-jasmonic acid from 1-10 ng/g (dry weight) by one to three orders of magnitude occur within a few minutes, e.g., after contact with microbial cell wallswounding, and in shoot spiralization Exogenous application of (methyl)jas-... 

Farmer, E. E. and C. A. Ryan, Octadecanoid precursors of jas-monic acid activate the synthesis of wound-inducible proteinase inhibitors. Plant Cell, 4, 129-134 (1992). 

The same conversion of 99 to 100 was also utilized by Fleet et al. [45] for the enantiospecific synthesis of (S)-quinuclidinol (103, Scheme 21). White et al. [46] employed the thermal rearrangement of the related vinyl ether 104 to aldehyde 105 for the total synthesis of monic acid C (106). 

A full account has been given of Curran s synthesis of pseudo-monic acid involving a Claisen rearrangement of a glycal derivative (see Vol. 18, p.247), together with further examples of such... 

---