Subergorgic acid

Wender PA, DeLong MA. Synthetic studies on arene-olefin cycloadditions. XII. Total synthesis of ( )-subergorgic acid. Tetrahedron Lett 1990 31(38) 5429-5432. 

The sequence of cyclohexene cleavage and aldol reaction on the dicarbonyl product gives ring-contracted cyclopentenes. This proved particularly valuable when Iwata6 wanted to make subergorgic acid 41 that has three five-membered rings awkwardly joined around a quaternary carbon atom. So crowded are these compounds that they are difficult to draw clearly. Ozono-lysis of the synthetic cyclohexene 38 gave the unstable dialdehyde 39 that cyclised by an aldol condensation to 40 and hence could be oxidised to 41. 

H-silphiperfol-5-ene 93 (R = 11, R2 = Me) [70], subergorgic acid 94 [71], crinipellin B 95 (formal synthesis) [72], (—)-retigeranic acid 96 (formal asymmetric synthesis) [73] were synthesized via intramolecular meta cycloaddition as key step (Sch. 18). In the same way, linear triquinane... 

Iwata s synthesis of subergorgic acid (30), a silphiperfolane derivative isolated from a gorgonian coral, involved the reductive fragmentation of the cyclobutanone (28) to the alcohol (29) via an intermediate aldehyde (Scheme 13). 

During the final stages of the total synthesis of (-)-subergorgic acid by L.A. Paquette and co-workers, the transposition of a tricyclic enone was needed. The enone was exposed to the Luche conditions and an 85 15 mixture of diastereomers was obtained. In order to achieve this level of diastereoselectivity, the reaction temperature had to be lowered to -50 °C instead of the usual 0 °C. The major product was formed via the exo attack of the carbonyl group by the hydride. The allylic alcohol was later converted to the corresponding sulfoxide followed by a Mislow-Evans rearrangement to the isomeric allylic alcohol. 

The intramolecular meta photocycloaddition of 5-phenyl-l-pentene derivatives has been applied very successfully by Wender and his group to the synthesis of a number of natural products. Some of their recent work in this area has been summarised in a paper based upon a lecture given at the Xlllth lUPAC Photochemistry Symposium. In addition, a communication has described the synthesis of the natural product subergorgic acid, (44), by a route which commences with intramolecular meta photocycloaddition of the phenylpentene... 

Styrene glycol, see P-30076 j5-Styrylacrylic acid, see P-20085 Styxenol A, in H-10219 Suavioside E, in K-10005 Subdivaricatic acid, S-20080 Subellinone, S-10126 Subelliptenone A, S-30095 Subelliptenone B, S-30096 Suberamic acid, in 0-10014 Suberamide, in 0-10014 Subergorgic acid, see 0-10063 Suberic acid, see 0-10014 Suberic anhydride, in 0-10014 Suberin A, in D-20149 Suberin B, in D-20149... 

Subergorgia suberosa and Terpenoids Crude extract subergorgic acid Inhibited the larval settlement of [84]... 

Parameswaran, P.S., Naik, C.G., Kamat, S.Y., Puar, M.S., Das, P., and Hedge, V.R. (1998) Studies on secondary metabolites from the Indian gorgonian Subergorgia suberosa isolation and characterization of four analogues of cardiotoxin subergorgic acid. /. Nat. Prod., 61, 832-834. 

Iwata, C., Takemoto, Y, Doi, M., and Imanishi, T. (1988) Stereoselective total synthesis of ( )- subergorgic add, a new type of angular triquinane sesquiterpene. /. Org. Chem., 53,1623-1628. Wender, P.A. and DeLong, M.A. (1990) Synthetic studies on arene-olefin cycloadditions. XII. Total synthesis of ( )-subergorgic acid. Tetrahedron Lett., 31, 5429-5432. 

Gilbert, J.C. and Yin, J. (2008) An approach toward the total synthesis of subergorgic acid. Tetrahedron, 64, 5482-5490. 

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