Quantum-Chemical Calculations of the Molecules 1-Methylbicyclo[4,1,0]Heptane 2,4-Spiroheptane by PM3 Method

140 This chapter presents the quantum‐chemical calculations of the molecules 1‐methylbicyclo[4,1,0]heptane, 2,4‐spiroheptane which has been performed by the PM3 method with geometry optimization of all parameters by the gradient method. Optimized geometric and electronic structure of these compounds is obtained. Their acid strengths (pKa = 28 and 30) are theoretically evaluated. We have established that the researched molecules relate to the class of very weak acids (pKa > 14).