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[摘要]:A new route to the DEF-ring building block of fredericamycin A has been elaborated. The five-step synthesis involves a photo-Wolff reaction as the key step and leads to carboxylic acid 2 in 27% overall yield, starting from the pyridine derivative 3. Two intermediates, the tricyclic ketones 6a and 7, are characterized by crystal structure analyses. |
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