Enantioselective Total Syntheses of (−)-Rhazinilam, (−)-Leucomidine B, and (+)-Leuconodine F

A divergent total synthesis of three structurally distinct natural products from imine 9 was accomplished through an approach featuring: 1) a Pd‐catalyzed decarboxylative cross‐coupling, and 2) heteroannulation of 9 with bromoacetaldehyde and oxalyl chloride to give tetrahydroindolizine 6 and dioxopyrrole 7, respectively. The former was converted into (−)‐rhazinilam, while the latter was converted into (−)‐leucomidine B and (+)‐leuconodine F. A substrate‐directed highly diastereoselective reduction of a sterically unbiased double bond by using a homogeneous palladium catalyst was developed. A self‐induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B. Be divergent: Concise total syntheses of (−)‐rhazinilam, (−)‐leucomidine B, and (+)‐leuconodine F were accomplished from the common intermediate A. A homogeneous palladium catalyst was exploited for the first time to accomplish a substrate‐directed highly diastereoselective hydrogenation of a sterically unbiased double bond. A self‐induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B.