Methane Monooxygenase Mimic Asymmetric Oxidation: Self-Assemblingμ-Hydroxo, Carboxylate-Bridged Diiron(III)-CatalyzedEnantioselective Dehydrogenation

Mimicking naturally occurring metalloenzymes to enrichthe diversity of catalytic asymmetric oxidation reactions is a long-standing goal for modern chemistry. Toward this end, a range ofmethane monooxygenase (MMO) mimic chiral carboxylate-bridged (mu-hydroxo) diiron(III) dimer complexes using salan as basal ligand andsodium aryl carboxylate as additive have been designed and synthesized.The chiral diiron complexes exhibit efficient catalytic reactivity indehydrogenative kinetic resolution of indolines using environmentallybenign hydrogen peroxide as oxidant. In particular, complexC9bearingsterically encumbered salan ligands and a 2-naphthoate bridge isidentified as the optimal catalyst in terms of chiral recognition. Furtherinvestigation reveals that this MMO mimic chiral catalyst can be readilygenerated by self-assembly under the dehydrogenation conditions. Theself-assembling catalytic system is applicable to a series of indolines with multiple stereocenters and diverse substituent patterns inhigh efficiency with a high level of chiral recognition (selectivity factor up to 153). Late-stage dehydrogenative kinetic resolution ofbioactive molecules is further examined.

Automated summary

Mimicking naturally occurring metalloenzymes for catalytic asymmetric oxidation reactions has been a long-standing goal in modern chemistry. In this study, a series of chiral diiron complexes mimicking methane monooxygenase (MMO) were designed and synthesized, exhibiting efficient catalytic reactivity in dehydrogenative kinetic resolution. The C9 complex was identified as the optimal catalyst with high chiral recognition.