Wacker‐Type Oxidation Using an Iron Catalyst and Ambient Air: Application to Late‐Stage Oxidation of Complex Molecules

A practical and general iron‐catalyzed Wacker‐type oxidation of olefins to ketones is presented, and it uses ambient air as the sole oxidant. The mild oxidation conditions enable exceptional functional‐group tolerance, which has not been demonstrated for any other Wacker‐type reaction to date. The inexpensive and nontoxic reagents [iron(II) chloride, polymethylhydrosiloxane, and air] can, therefore, also be employed to oxidize complex natural‐product‐derived and polyfunctionalized molecules. On air: A convenient and general iron‐catalyzed oxidation of internal olefins, electron‐deficient olefins, and styrenes to ketones by using 1 atm of air as the sole oxidant has been developed. This method efficiently incorporates atmospheric O2 into synthetically useful compounds under mild reaction conditions, which renders it environmentally benign, economical, and operationally simple.