All-Trans geranylgeraniol

Mu, Y.Q., and Gibbs, R.A. (1995). Coupling of isoprenoid triflates with organoboron nucleophiles synthesis of all-trans-geranylgeraniol. Tetrahedron Lett 36 5669-5672. 

A synthesis of all-tran -geranylgeraniol and the assignment of its C n.m.r. spectrum has been recorded. A highly oxygenated derivative of geranyl-geraniol, ligantrol (183), has also been synthesized. " ... 

Synthesis of All-t/a/is-Geranylgeraniol. The type of alkylation described above for the synthesis of bacillariolide III is widely used in the synthesis of natural products due to the mild reaction conditions and high stereospecificity. The formation of the C-C bond takes place when activated a-sulfonyl car-banions derived from (3-ketosul tones, a-sulfonyl sulfones or, less often, allylic sulfones react with the H-allyl palladium complex. In the synthesis of all-trans-geranylgeraniol, the a-sulfonyl carbanion adds to the Ti-allylpalladium complex of 2-(prop-l-en-2-yl)oxirane. Final reductive desulfonylation affords the desired compound, as depicted in Eq. 147.254... 

A different picture emerges when this template effect is extended to flexible substrates such as all-tran.v-farnesol and all-/rani-geranylgeraniol. Thus the ester 4 under the conditions of Sharpless epoxidation is epoxidized to the 6,7-epoxide and the 10,11-epoxide in the ratio 40 60, with only negligible reaction at the allylic position. Similarly the ester 5 is converted into the 6,7-epoxide, the... 

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