Studies on the Synthesis of 1-Azaspiroundecanes Related to Histrionicotoxin

Article abstract of DOI:10.1021/jo00279a014

3-Methoxybenzaldehyde was converted into 4-(3-methoxyphenyl)butylamine (4), and the derived hydrochloride was reduced with Li/NH3/EtOH to give the spirocyclic keto amine 6.The reduction of 6 and urethane derivatives 13 and 14 to give the corresponding cis and trans alcohols 9/10, 15/16, and 17/18 was studied.The keto amine 6 upon attempted ketalization underwent rearrangement to give the α,β-unsaturated imine 11.Treatment of 6 with N-chlorosuccinimide, followed by DBU, gave the aziridine 21.The amide 25 was converted derectly into 1-azaspiro<5.5>undecane-2,8-dione (24) by Birch reduction and acid hydrolysis.The dione 24 underwent stereospecific reduction with LS-Selectride to give the cis alcohol 30.