Synthesis of (–)-Himalensine A
Total Synthesis of (–)-Himalensine A.
J. Am. Chem. Soc. 2017;
18 January 2018 (online)
Key words(–)-himalensine A - daphniphyllum alkaloid - amidofuran - Diels–Alder reaction - Negishi coupling - Stetter cyclization
(–)-Himalensine A is a highly congested alkaloid featuring a trinorcalyciphylline A skeleton. Dixon, Paton, and co-workers report its first enantioselective synthesis in 23 steps involving an intramolecular amidofuran Diels–Alder reaction (see also Synfacts 2018, 14, 203).
The enantioselective, intramolecular Diels–Alder reaction of B afforded tetracycle D. A Stetter cyclization of L using NHC catalyst M forged the final ring of the carbon framework. Subsequent amide reduction completed the total synthesis.