Transannular Diels–Alder Studies of 14-Membered cis–trans–trans Macrocyclic Trienes Having Allylic Ether or Enone Dienophile

Highly convergent, malonate alkylation based syntheses of the model macrocycles and their title investigations are reported. In the allylic ether dienophile case, a preference for tricycles with equatorial ether position was found at the transition state level. Ab initio calculations also show that the origin of this preference is not only steric but stereoelectronic as well. The enone dienophile case indicates that when the enone system is not totally twisted out of planarity by the macrocyclic environment, the Diels–Alder reaction follows the usual trend in terms of dienophile activation.