Journal article
Studies of the Formation of All-carbon Quaternary Centres, en route to Lyngbyatoxin A. A Comparison of Phenyl and 7-Substituted Indole Systems
Copper mediated allylic substitutions and conjugate additions to geranyl, cinnamyl and allylic indole compounds have been investigated with the aim of finding a method for the creation of the all-carbon quaternary centre present in the natural product lyngbyatoxin A. Reaction conditions have been found giving a 68% S(N)2' selectivity in the copper mediated addition of PhMgBr to geranyl chloride, as well as 99% and 95% S(N)2' selectivity in the copper catalysed addition of EtMgBr to cinnamyl chloride and acetate, respectively.
When the optimised reaction conditions were applied to the corresponding allylic compounds containing a 7-substituted indole moiety, the regioselectivity was reversed giving only the S(N)2 product. The allylic indole-containing substrates were also found to be unproductive in Pd- or Mo-catalysed S(N)2'-type substitution reactions.
In related studies, copper catalysed conjugate addition of EtMgBr to the tricyclic lactam 6-methyl-pyrrolo[3,2,1-ij]quinolin-4-one gave a maximum of 20% of the 1,4-addition product.
Language: | English |
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Year: | 2004 |
Pages: | 1447-1455 |
ISSN: | 14770539 and 14770520 |
Types: | Journal article |
DOI: | 10.1039/b401490a |
ORCIDs: | Tanner, David |
Cinnamates Copper Cyclization Heterocyclic Compounds, 3-Ring Indoles Lactams Lithium Chloride Lyngbya Toxins Magnetic Resonance Spectroscopy Molecular Conformation Molecular Structure Molybdenum Organometallic Compounds Palladium Solvents Temperature Terpenes cuprous chloride ethyl magnesium bromide lyngbyatoxin A