Hydroboration-Carbon Monoxide Insertion of Bis-Olefinic Amine Derivatives. Synthesis of δ-Coniceine, Pyrrolizidine, (+/-)-Heliotridane, and (+/-)-Pseudoheliotridane

Article abstract of DOI:10.1021/jo00347a024

The hydroboration-carbon monoxide insertion of several bis-olefinic derivatives has provided facile preparations of N-(carbomethoxy)-5-azacyclooctanone (6), N-(carbobenzyloxy)-5-azacyclooctanone (9), and N-(carbobenzyloxy)-5-cyclononanone (18).Of the hydroboration protocols examined, thexylborane-cyanidation proved to be the most useful.Reductive ring closure of 9 and of 18 gave 26 and 27, respectively.Methylation of 9 followed by reduction afforded 29 and 30.