Conjugate addition of 2- and 4-pyridylcuprates: an expeditious asymmetric synthesis of natural (-)-evoninic acid.
[reaction: see text] The scope and limitations of the conjugate addition of 2- and the first 4-pyridyl Gilman homocuprates to various alpha,beta-unsaturated Michael acceptors are delineated. The conjugate addition of the cuprate of 2-bromo-3-methylpyridine to (E)-methyl crotonate then diastereoselective enolate alkylation and lipase-mediated enantioselective ester hydrolysis have enabled an efficient four-step first asymmetric synthesis of the Celastraceae sesquiterpenoid esterifying ligand (-)-(1'S,2'S)-evoninic acid.
Spivey
Alan C
AC
Department of Chemistry, Imperial College, London, SW7 2AY, U.K. a.c.spivey@imperial.ac.uk
Shukla
Lena
L
Hayler
Judy F
JF
D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D029753:Celastraceae / Q000737:chemistry / Q000378:metabolism; D004986:Ether / Q000737:chemistry; D008745:Methylation; D015394:Molecular Structure; D011422:Propionates / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
D001688:Biological Products; D011422:Propionates; D011725:Pyridines; C519123:evoninic acid; D004986:Ether; C023666:pyridine