178. Stereoselective Total Syntheses of (+/-)-Chanoclavine I and (+/-)-Isochanoclavine I by an Intramolecular Nitrone-Olefin/Cycloaddition

Article abstract of DOI:10.1002/hlca.19800630639

The racemic alkaloids chanoclavine I (1) and isochanoclavine I (2) have been synthesized stereoselectively from indole-4-carbaldehyde (3) by a sequence of 11 operations in overall yields of 14percent and 2.4percent, respectively.The key step 6->8 (Scheme 2) involves a transient nitrone 7 which undergoes a regio- and stereoselective intramolecular cycloaddition to a 1,2-disubstituted olefinic bond.