A practical synthesis of (+/-)-alpha-isosparteine from a tetraoxobispidine core.
[reaction: see text] The title alkaloid was synthesized in racemic form from 3,7-diallyl-2,4,6,8-tetraoxo-3,7-diazabicyclo[3.3.1]nonane (7) by a regioselective diallylation reaction followed by double ring-closing olefin metathesis and exhaustive reduction. Tetraoxobispidine 7 was itself prepared in three simple operations from dimethyl malonate. The entire sequence to alpha-isosparteine was conducted on a multigram scale and proceeded without recourse to chromatography.
Blakemore
Paul R
PR
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA. paul.blakemore@science.oregonstate.edu
Kilner
Colin
C
Norcross
Neil R
NR
Astles
Peter C
PC
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D008314:Malonates / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013034:Sparteine / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D019086:Bridged Bicyclo Compounds, Heterocyclic; D008314:Malonates; C495809:bispidine; D013034:Sparteine; C005230:methyl malonate