Abstract A new synthetic method of (2E, 4E)-dienals by four-carbon homologation of aldehydes is described. γ-trimethylsilyl crotonaldimine 2, easily generated from N-ter-butyl- crotonaldimine 1, LDA and ClSiMe 3, reacts with aldehydes in the presence of catalytic CsF in DMSO at rt→ 100 C to afford homologous aldehydes 3 in good yields and with excellent (E, E)-selectivities.
