ROOM-TEMPERATURE, ENDO-SPECIFIC 1-AZA-1,3-BUTADIENE DIELS-ALDER REACTIONS - ACCELERATION OF THE LUMO(DIENE)-CONTROLLED [4+2]-CYCLOADDITION REACTIONS THROUGH NONCOMPLEMENTARY AZADIENE SUBSTITUTION

: A preparation of N-sulfonyl-2-(ethoxy-carbonyl)-l-aza-l,3-butadienes 5–6 is described and is based on the use of the stabilized Wittig reagent 1 and implementation of a subsequent room temperature, in situ homolytic oxime O-sulfinyl N-sulfonyl rearrangement. The 4π participation of the electron-deficient 1-aza-1,3-butadienes 5–6 in room temperature, endo-specific LUMOdiene-controlled [4 + 2] cycloaddition reactions is described and represents a demonstration of the acceleration of the Diels-Alder reaction of 1-aza-1,3-butadienes achieved through noncomplementary azadiene substitution. © 1990, American Chemical Society. All rights reserved.