N,N-Dialkylhydrazones as the Imine Component in the Staudinger-Like [2+2] Cycloaddition to Benzyloxyketene We thank the Dirección General de Investigación Científica y Técnica (grants BQU 2001-2376 and PPQ 2000-1341) and the Junta de Andalucía for financial support. We also thank the Ministerio de Educación y Ciencia for a doctoral fellowship to A.F.