180857-81-2Relevant articles and documents
-
Moyroud,Gelin,Chene,Mortier
, p. 8525 - 8534 (2007/10/03)
Cross coupling reactions of lithiated 2,5-piperazinedione anions with gramine methosulfate and alkylhalides were shown to be catalyzed by copper reagents, e.g. dilithium tetracholorocuprate and copper (1) iodide. Based on this findings, the results of the first method for preparation of racemic thaxtomins are reported. Compound 1c, chosen as a synthetic model, was prepared in five steps in 19% overall yield. The key step was reaction of the lithiated anion of sarcosine anhydride with gramine methosulfate in the presence of a catalytic amount of dilithium tetrachlorocuprate in THF. The remainder of the sequence involved protection of the indole NH, aldol condensation with 3- benzyloxybenzaldehyde, bromohydrin formation and catalytic hydrogenation.