Hydration of 5-Oxo-1-Alkynes by a One-Pot Oxy-Iodination/Reduction Sequence: Synthesis of Methyl Ketones with Anchimeric Assistance

Methyl ketone derivatives can be accessed from 5-oxo-1-alkynes in an iodine-initiated hydration of the terminal alkynes. Use of molecular iodine in this manner is novel, inexpensive and a greener alternative to the traditional use of transition metal catalysts. Herein, we report the results of a methodology study which sheds light on the underlying mechanism of this new, metal-free reaction. Our findings indicate that the hydration of the alkyne proceeds via an important anchimeric assistance in which the neighboring keto group participates with a 5-exo-dig cyclization.