Formation of 10/12/14‐Membered Rings is Favored over 5/6/7‐Membered. An Unexpected Result from Oxazole Chemistry
Eur. J. Org. Chem. 2019, (30), 4962-4967
Base‐promoted cyclization of N‐Boc‐ω‐(4‐(chloromethyl)oxazol‐5‐yl)alkylamines led to the corresponding “dimerization” products containing fused 10‐, 12‐, and 14‐membered rings. Experimental data showed that the formation of these ring systems is favored over the corresponding 5‐/6‐/7‐membered ones, which was partially confirmed by DFT calculations; this effect was especially significant in the case of the 5‐/10‐membered pair.