Anolignan

Use of an ethylene atmosphere can be beneficial to increase catalyst selectivity and reactivity [176] but it can also lead to the unwanted production of the corresponding 1,3-butadiene due to competition of ethylene with the desired cross-partner [177]. On the other hand ECM with ethylene as the cross-partner can be used as a very convenient method for the production of 2,3-disubstituted butadiene systems. The successful application of this methodology has for example been achieved by Mori et al. in the total synthesis of anolignan A (Scheme 3.20) [178]. 

Scheme 3.20 ECM with ethylene to synthesise anolignan A precursor 120...

Using this procedure, total synthesis of anolignane A is achieved. It is interesting that two methylene groups generated from ethylene are introduced on the alkyne... 

Construction of 1,3-diene moieties from alkynes and ethylene is a unique methodology for the synthesis of 1,3-dienes. Mori used this strategy for the synthesis of anolignan A. Two methylene groups from ethylene are introduced onto the alkyne carbon of 109 using Ig to give 1,3-diene 110. From this compound, short-step synthesis of anolignan A is achieved (Scheme 41). ... 

Termilignan and anolignan B isolated from Terminalia bellerica inhibited the chloroquine-susceptible strain of Plasmodium falciparum assayed, with IC50 of 9.6 and 20.5 pM respectively [160],... 

Mori M, Tonogaki K, Nishiguchi N. Syntheses of anolignans A and B using ruthenium-catalyzed cross-enyne metathesis. J. Org. Chem. 2002 67 224- 226. 

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