Precipiton strategies applied to the isolation of α-substituted β-ketoesters

Diaryl alkene 1Z is a ‘precipiton’, a protecting group that allows reaction products to be isolated by simple filtration. Here we illustrate the use of this protecting group for the preparation and isolation, without distillation or chromatography, of pure α-substituted β-ketoesters. The precipiton 1Z was prepared in 43% overall yield. It is anticipated that development of precipiton-based syntheses will provide a new alternative for automated reaction product isolation that may be useful for bench-scale and process-scale chemical preparations.