From Olefins to Ketones via a 2‐Rhodaoxetane Complex

Quantitative oxygenation of 1,5‐cyclooctadiene to 4‐cyclooctenone with molecular oxygen by a rhodium complex proceeds via a 2‐rhoda(III)oxetane intermediate (see scheme), which undergoes a facile β‐elimination reaction to give the unsaturated ketone selectively instead of the epoxide.