Fig. 5: Investigations on the reaction mechanism.
From: Pyrrolidine synthesis via ring contraction of pyridines
a UV-Vis spectra of benzene solutions of pyridine (a blue line), silylborane (a yellow line), and a mixture of pyridine and silylborane (a red line). b Time course analysis of the ring contraction reaction of pyridine with silylborane. c Interconversion between the products 2 and 1,2-dihydropyridines 12. d An example of thermolysis and photolysis of a particular Hantzsch ester derivative reported by Biellmann. e DFT calculations (ωB97XD/def2-TZVPP/SMD(benzene)). Grel refer to Gibbs’ free energies relative to that of pyridine and PhMe2SiBpin in kcal/mol.
