title: Asymmetric Organocatalytic Stepwise [2+2] Entry to Tetra-Substituted Heterodimeric and Homochiral Cyclobutanes.
abstract: An asymmetric synthesis of tetra-substituted cyclobutanes involving an organocatalytic, stepwise [2+2]-cycloaddition is described. The secondary-amine-catalyzed method allows for the hetero-dimerization of two different cinnamic-acid-derived sub-units, opening a novel one-step assembly to densely functionalized, head-to-tail coupled dimeric cyclobutanes in high enantiomeric excess. A series of selective synthetic interconversions in these sensitive cycloadducts is also described.
authors.affiliation: Department of Chemistry and Chemical-Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1, Canada.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Nielsen
authors.affiliation: Department of Chemistry and Chemical-Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1, Canada.
authors.forename: Hilary A
authors.initials: HA
authors.lastname: Jenkins
authors.affiliation: Department of Chemistry and Chemical-Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1, Canada. jmcnult@mcmaster.ca.
authors.forename: James
authors.initials: J
authors.lastname: McNulty
keywords: asymmetric synthesis; cyclobutanes; lignan dimers; organocatalysis