Synthesis of N-Benzylated Anilines from the Reaction of Anilines and Benzyl Chloroformate
Pati, H. N.; Weisbruch, P.; Lemon, A.; Lee, M. Synthesis of N-Benzylated Anilines from the Reaction of Anilines and Benzyl Chloroformate. Synth. Commun. 2004, 34, 933-940.
Reactions of benzyl chloroformate with a series of substituted anilines produced Nâ€carbobenzyloxy â€œCBZâ€ products along with the unexpected Nâ€benzylated â€œBnâ€ compounds. Reaction of aniline, 1a, gave the CBZ, or 2a, and Bn, or 3a, products in 29% and 14% yield, respectively. For 2â€nitroâ€, 2â€bromoâ€, and 2â€bromoâ€5â€nitroanilines, the Nâ€benzylated compounds were produced exclusively. However, 2â€methoxyâ€, 4â€bromo, 4â€iodo, and 4â€ethylanilines gave mainly CBZ products. Other compounds reported in this study gave mixtures of the two products. For 4â€chloroâ€3â€nitroaniline, in addition to the Bn and CBZ products (53% and 14% yield, respectively), a N,Nâ€dibenzylated product was isolated in 27% yield. Collectively, the results indicated that electronâ€withdrawing groups, particularly at the ortho position, directed the formation of Bn compounds, whilst electronâ€donating groups, especially at the ortho and para positions, favored the synthesis of CBZ products.