title: A useful methoxyvinyl cation equivalent: α-t-butyldimethylsilyl-α-methoxyacetaldehyde.
abstract: Described are the synthesis and application of α-t-butyldimethylsilyl-α-methoxyacetaldehyde as a formal methoxyvinyl cation equivalent. Addition of Grignard reagents to the title aldehyde, followed by treatment of the intermediate β-hydroxysilanes with KH, gives good yields of largeZ-methoxyvinylated products. Assuming a Peterson-like elimination mechanism, one can infer that the Grignard addition proceeds with highsynselectivity. These results are consistent with a chelation control model involving coordination to the α-methoxy group in the title aldehyde rather than an alternative stereoelectronic Felkin-Anh-type model. It must be noted that a steric Felkin-Anh model also accounts for the observed stereochemistry. All told, the title reagent can be employed to efficiently append aZ-configured methoxyvinyl group to an appropriate R-M species, in two steps.
authors.affiliation: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: McCune
authors.affiliation: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Beio
authors.affiliation: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Friest
authors.affiliation: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Ginotra
authors.affiliation: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Berkowitz
keywords: Peterson elimination; chelation control; methoxyvinylation; steric Felkin-Anh model; α-silyl-α-methoxyacetaldehyde