A radical cascade approach to the skeleton of a-Cyclopiazonic Acid

3-Nitrophthalic acid 2.04 was transformed into 2.10 in 38% yield. Vinylglycine derivative was synthesised from D-Methionine 2.12 in 42% yield. (For image see abstract in pdf) Compounds 2.10 and 2.16 were coupled using Grubbs’ 2nd generation catalyst creating 2.25. Unfortunately attempts to oxidise the benzylic position were unsuccessful. (For image see abstract in pdf) An alternative approach was investigated using diene 2.40 derived from a precursor to 2.10 and allyl bromide 2.35. Attempts to displace bromide under anionic conditions were futile. The use of palladium formed conjugated dieneamine 2.65. (For image see abstract in pdf) Deprotection, oxidation and elaboration of 2.10 prior to cross metathesis allowed the synthesis of 2.114, which when subjected to radical conditions, formed a diastereomeric mixture of 2.220. (For image see abstract in pdf)