Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (+/-)-hippodamine and (+/-)-epi-hippodamine.
BACKGROUND
Hippodamine is a volatile defence alkaloid isolated from ladybird beetles which holds potential as an agrochemical agent and was the subject of a synthesis by our group in 2005.


RESULTS
Two enhancements to our previous syntheses of (+/-)-hippodamine and (+/-)-epi-hippodamine are presented which are able to shorten the syntheses by up to two steps.


CONCLUSIONS
Key advances include a two-directional homologation by cross metathesis and a new tandem reductive amination/double intramolecular Michael addition which generates 6 new bonds, 2 stereogenic centres and two rings, giving a single diastereomer in 74% yield.
Newton
Annabella F
AF
School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK. pcxan4@nottingham.ac.uk
Rejzek
Martin
M
Alcaraz
Marie-Lyne
ML
Stockman
Robert A
RA