摘要:
The synthetic intermediate 2 corresponding to the C(26)-C(37) fragment of calyculin A (1) has been synthesized. Key transformations include the efficient one-pot construction of the oxazole system embedded in 1 without epimerization-alpha [C(30)] to the ring, and the in situ formation of the dimethylamine by opening an N-methyllactam with Meerwein's reagent and trapping the resultant methylamine with formaldehyde.