title: Three-component glycolate Michael reactions of enolates, silyl glyoxylates, and α,β-enones.
abstract: Silyl glyoxylates react with enolates and enones to afford either glycolate aldol or Michael adducts. Product identity is controlled by the countercation associated with the enolate. Reformatsky nucleophiles in the presence of additional Zn(OTf)(2) result in aldol coupling (A), while lithium enolates provide the Michael coupling (B). Deprotonation of the aldol product A with LDA induces equilibration to form the minor diastereomer of Michael product B. This observation suggests that formation of the major diastereomer of Michael product B does not occur via an aldol/retro-aldol/Michael sequence.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Schmitt
authors.forename: Ericka J
authors.initials: EJ
authors.lastname: Malow
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Johnson
mesh_terms: D002384:Catalysis; D003500:Cyclization; D006038:Glyoxylates / Q000138:chemical synthesis* / Q000737:chemistry*; D018020:Lithium Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism; D014297:Trimethylsilyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D006038:Glyoxylates; D018020:Lithium Compounds; D014297:Trimethylsilyl Compounds