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DOI: 10.1055/s-2007-991211
Synthesis of (+)-Azaspiracid-1
Contributor(s):Philip KocienskiHarvard University, Cambridge, USA
Total Synthesis of (+)-Azaspiracid-1. Part II: Synthesis of the EFGHI Sulfone and Completion of the Synthesis
Angew. Chem. Int. Ed. 2007, 46: 4698-4703
Publication History
Publication Date:
24 October 2007 (online)
Key words
sulfone anions - hetero-Diels-Alder reaction - glyoxylate-ene reaction - directed aldol reaction - cross-metathesis
Significance
(-)-Azaspiracid 1 is a neurotoxin associated with seafood poisoning. The synthesis of the (+)-enantiomer depicted features the deft use of metallated sulfones in two of the key fragment linkage reactions (A+B) and (E+F) and the use of BOX catalysts J, K, and L in the synthesis of fragments F, G, I, and H, respectively.
Comment
A preceding paper (Angew. Chem. Int. Ed. 2007, 46, 4693) described the synthesis of fragment A. The entire synthesis required only 27 linear steps and gave the target in 2.7% overall yield. The first synthesis of (-)-azaspiracid-1 in 39 linear steps was reported by Nicolaou et al. (Angew. Chem. Int. Ed. 2004, 45, 2609).