Theoretical predication of Diels Alder reactions of highly strained dienophiles
Abstract Using density functional theory M06 2X functional in combination with 6 311++G* basis set, we have obtained six types of highly strained dienophiles (1 6) The Diels Alder reactions of 1 6 with butadiene (A) cyclopentadiene (B) and 3,6 bis(trifluoromethyl) tetrazine (C) have been investigated. Calculated results show that these Diels Alder reactions are both thermodynamically and kinetically feasible. The endo Diels Alder reactions of 1 6 with A and B are more favorable than their exo Diels Alder reactions, which originates from the distortion energy differences of A and B. The low activation energy of the Diels Alder reactions of 1 6 with C arises from the electron withdrawing group CF3 in C, which is consistent with the previous results (J. Am. Chem. Soc. 2013, 135, 15642) The Diels Alder reactions of 1 6 with the three dienes give a family of novel propellanes but not six membered carbocycles.