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(Z,E,E)-humulene. Conformational analysis and transannular cyclization

✍ Scribed by Haruhisa Shirahama; Grudial S. Arora; Eiji Ōsawa; Takeshi Matsumoto

Publisher
Elsevier Science
Year
1983
Tongue
French
Weight
277 KB
Volume
24
Category
Article
ISSN
0040-4039

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✦ Synopsis

Geometries and populations for four possible conformers of (L,i,E)-humulene (,j) were obtained by molecular mechanics calculations. Treatment of L with mercury salt gave 3,7-epoxy-3,6-secoprotoilludane (2) and 9,10-epoxide of 1 afforded tetramethylbicyclo[7.2.0]undecadienols (l,O,lJ) on treatment with TMSOTf. Not a small number of sesquiterpenes having versatile carbon framework such as himachalane, longipinane,longibornane and so forth have been considered to be biogenetically derived from c-&-farnesyl pyrophosphate through a protonated form of (g,E,Q-humulene (J) (Scheme l).') However, no information about 1 has been available since it has not been found in nature and not synthesized so far.

2)

Recently we reported the first synthesis of this biogenetically important compound.

In this paper we wish to describe conformational analysis and chemical cyclization of J.

Conformational analysis of J was carried out in the same procedure as that used in the analysis of (E,E,E)-humulene (,2). 3)

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