Silver, Fern

The structure of calomelanolactone (337), a co-metabolite of pterosin Z (338) in Pityrogramma calomelanos ( silver fern ), has been determined by X-ray crystallographic analysis. ... 

The central six-membered ring unit in the illudalane or pterosin class of sesquiterpenes makes them a suitable target for a proof of the synthetic power of the transition-metal-catalyzed [2 + 2 + 2] alkyne cycloaddition in natural product synthesis. A first example in this field was provided by the intramolecular version of the [2 + 2 + 2] alkyne cyclotrimerization in the synthesis of calomelanolactone (15) [8] and pterosin Z (16), both of which have been isolated Ifom the silver fern Pityrogramma calome-lanos (Scheme 7.4) [9]. Wilkinson s complex served here as the catalyst, and the cyclotrimerization of triyne 13 proceeded at room temperature to give the tricycle 14. The latter was used as a common synthetic intermediate for completion of the synthesis of calomelanolactone (15) and pterosin Z (16) within four and three synthetic steps, respectively. 

WoUenweber, E. and Dietz, V. H. 1980. Elavonoid patterns in tbe farina of goldback and silver-back ferns. Biochem. Syst. Ecol. 8 21-33. 

Silver, J. Marsh, P. J. Withnall, R. Fern, G. R. Extended Abstracts of the First International Conference on Science and Technology of Emissive Displays and Lighting, San Diego, CA, Nov 12-14, 2001 147-150. 

Sosa-Sanchez JL, Galindo A, Gnecco D, Bernes S, Fern GR, Silver J, Sosa-Sanchez A, Enriquez RG (2002) J Porphyrins Phthalocyanines 6 198... 

G. Fern, J. Silver, M. J. Snowden, and R. Withnall, unpublished data, patent pending,... 

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