The pentacyclic core of ecteinascidins was constructed from two fundamental building blocks, the 1,2,3,4-tetrahydroisoquinoline derivative and the substituted phenylalanine derivative, via 8 steps using readily available L-Dopa as starting material. The key steps involve coupling of the two aforementioned building blocks, regioselective reduction of the I I-carbonyl group of the key intermediate
... [Show full abstract] piperazine-1,4-dione derivative, and intramolecular Pictet-Spengler cyclization.