- An Unusual Skeletal Rearrangement in the Biosynthesis of the Sesquiterpene Trichobrasilenol from Trichoderma
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The skeletons of some classes of terpenoids are unusual in that they contain a larger number of Me groups (or their biosynthetic equivalents such as olefinic methylene groups, hydroxymethyl groups, aldehydes, or carboxylic acids and their derivatives) than provided by their oligoprenyl diphosphate precursor. This is sometimes the result of an oxidative ring-opening reaction at a terpene-cyclase-derived molecule containing the regular number of Me group equivalents, as observed for picrotoxan sesquiterpenes. In this study a sesquiterpene cyclase from Trichoderma spp. is described that can convert farnesyl diphosphate (FPP) directly via a remarkable skeletal rearrangement into trichobrasilenol, a new brasilane sesquiterpene with one additional Me group equivalent compared to FPP. A mechanistic hypothesis for the formation of the brasilane skeleton is supported by extensive isotopic labelling studies.
- Murai, Keiichi,Lauterbach, Lukas,Teramoto, Kazuya,Quan, Zhiyang,Barra, Lena,Yamamoto, Tsuyoshi,Nonaka, Kenichi,Shiomi, Kazuro,Nishiyama, Makoto,Kuzuyama, Tomohisa,Dickschat, Jeroen S.
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supporting information
p. 15046 - 15050
(2019/09/12)
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- A short total synthesis of (±)-isoafricanol and two of its isomers
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The syntheses of (±)-isoafricanol and two of its isomers were achieved from 2,5,5-trimethylcyclohex-2-en-1-ol. The key step was a photoreductive radical cyclisation of an unsaturated ketone.
- Cossy, Janine,BouzBouz, Samir,Mouza
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p. 621 - 622
(2007/10/03)
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- Synthetic Approach for (+)-Africanol
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Synteses of (+)-africanol (1) and (+)-isoafricanol (2) were attempted by reductive radical cyclization of (1S,2S,8S)-2-(4'-butenyl)-1,5,5-trimethyl-bicyclo-3-octanone derived from (1R,2S,4S,8S)-4-alkoxy-1,6,6-trimethyl-tricyclo2,4>nonane.This cyclization gave (+)-1 and (+)-2 as minor components, together with trans fused epimers as major components.
- Sugimura, Takashi,Futagawa, Tohru,Tai, Akira
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p. 2295 - 2298
(2007/10/02)
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- CONFORMATIONALLY SELECTIVE TRANSANNULAR CYCLIZATION OF HUMULENE 9,10-EPOXIDE. SYNTHESIS OF THE TWO SKELETALLY DIFFERENT CYCLOHUMULANOIDS: DL-BICYCLOHUMULENONE AND DL-AFRICANOL
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Two cyclohumulanoids, dl-bicyclohumulenone (4) and dl-africanol (7) were synthetized through newly developed conformationally selective transannular cyclization of humulene 9,10-epoxide (2).The epoxide 2 was converted to a bicyclohumulenediol diacetate 3a in 70percent yield by treatment with BF3.Et2O-Ac2O, while treatment of 2 with trimethylsilyl trifluoromethansulfonate gave an africen-ol (5a and 5b) in 80percent yield.The two intermediates 3a and 5a furnished the natural products 4 and 7 in 30 and 8 percent yield from 2 respectively.
- Shirahama, H.,Hayano, K.,Kanemoto, Y.,Misumi, S.,Ohtsuka, T.,et al.
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p. 4835 - 4838
(2007/10/02)
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