Vinhaticoate methyl

These natural substances range from simple monosubstituted benzo-furans, such as 5-methoxybenzofuran (44) (which has bactericidal propertiesand plays an important part in the biosynthesis of natural benzofurans ) to more complex benzofurans. They include polycyclic compounds with one naphthofuran or phenanthrofuran ring (tanshinones, etc.) and furanic diterpenes [methyl vinhaticoate (45), methyl voucapenate (46), viridine (47)i5o-i52 fungicidal metabolite)]. 

Spencer et at. used this reaction as a key step in the synthesis of racemic methyl vinhaticoate (6), a tetracyclic furanoid diterpene. Thus treatment of the a-methoxy-methylene ketone (4) with ethyl diazoacetate in the presence of copper sulfate... 

A synthesis of methyl vinhaticoate and methyl vouacapenate has been described. The key steps involved the conjugate addition of dimethylcopper lithium to (128), prepared from podocarpic acid, the transformation of the product (129) into the methoxymethylene ketone (130), and the formation of the furan ring (131) by the copper-catalysed addition of ethoxycarbonylcarbene. 

The synthesis of methyl vinhaticoate, a furanoid diterpene constituent of South American hardwood, illustrates a novel furan synthesis based on the 1,4-addition of carbethoxycarbene to cy-methoxymethylene ketonesJ... 

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