One-step synthesis of nitrogen-containing medium-sized rings via α-imino diazo intermediates.

Eight- and 9-membered dioxazocines and dioxazonines are readily synthesized starting from N-sulfonyl-1,2,3-triazoles in a single-step procedure. A perfect regioselectivity and generally good yields (up to 92%) are obtained under dirhodium catalysis using 1,3-dioxolane and 1,3-dioxane as solvents and reagents.