EXPERIMENTAL AND COMPUTATIONAL STUDY OF 6-exo AND 7-endo CYCLIZATION OF ARYL RADICALS FOLLOWED BY TANDEM SRN1 SUBSTITUTION

PEISINO, L. E.; PIERINI, A. B.

Foz do Iguaçu

Congreso; 12 Conferencia Latinoamericana de Físico-Química Orgánica 12th Latin American Conference on Physical Organic Chemistry; 2013

The reaction of N-allyl-N-(2-halobenzyl)-acetamides and derivatives was investigated in liquidammonia under irradiation with the nucleophiles Me 3Sn− , Ph2P− and O2NCH2− (Figure 1). Thesereactions are proposed to occur through the intermediacy of aryl radicals which by intramolecular 6-exo or 7-endo attack to a double bond afford cyclic aliphatic radicals. 1 These radicals react along thepropagation steps of the SRN1 chain cycle2 to afford the cyclic substituted compounds as mainreaction products; the product distribution being dependent on the relative rates of each ring closuremode.Following this procedure, novel substituted 1,2,3,4-tetrahydroisoquinolines and substituted 4,5-dihydro-1H-benzo[c]azepin-2(3H)-yl ethanones were obtained in good yields (Figure 1).Figure 1The reactions were modelled with the B3LYP-D functional and the 6-31+G* basis set, which providea rational understanding that relates the product distribution to the structure of the cyclic aliphaticradicals proposed as intermediates and the kinetic of their formation.(1) Vaillard, S. E.; Postigo, A.; Rossi, R. A. J. Org. Chem. 2002, 67, 8500–8506.(2) Rossi, R. A.; Pierini, A. B.; Peñéñory, A. B. Chem. Rev. 2003, 103, 71–167.