Reaction of Optically Active α-Aminoallenylstannanes with Aldehydes Formed in Situ from the Lewis-Acid-Catalyzed Rearrangement of Epoxides

Reaction of optically active α-oxazolidinonylallenylstannanes
with oxiranes in the presence of BF3·OEt2 produced β-hydroxypropargylamines with high syn diastereoselectivity and
high enantioselectivity through an initial Lewis-acid-catalyzed rearrangement of the oxirane to the corresponding
aldehyde via an alkyl, aryl, or hydride shift. This permits
the use of readily available oxiranes as alternatives to
aldehydes that are difficult to prepare and/or unstable.