The Roskamp reaction,[1] a Lewis acid catalyzed reaction of alkyl diazoesters with aldehydes, is a powerful and useful synthetic method to construct β-keto carbonyl compounds, which have been utilized in the synthesis of natural products [2](Scheme 1). An asymmetric variant of this transformation was previously effected using the chiral-auxiliary- based approach with a camphorsultam-derived diazocarbonyl compound.[3a] To the best ...