SEARCH Articles Figures Tables Boat-like transition states Diels-Alder reactions Characterization of Diels-Alder Transition Structures Diels-Alder reaction endo transition state Diels-Alder reaction transition state structure Diels-Alder transition state charge transfer Transition hetero-Diels-Alder reactions Transition state Diels Alder reaction Transition state butadiene Diels-Alder reactions Transition state for the Diels-Alder reaction Transition state in Diels-Alder reactions Transition structures Diels-Alder Unsymmetrical Diels-Alder transition structures