Design and Synthesis of C₄‐Symmetric Axially Chiral β‐Aryl Porphyrins and Application for Supporting Ir(III)‐Catalyzed Enantioselective C−H Alkylation

A hitherto unknown class of C 4 ‐symmetric C aryl −C β (C 3 , C 8 , C 13 , C 18 ) axially chiral porphyrins has been synthesized and the application of their iridium (Ir) complexes in catalytic asymmetric C(sp 3 )−H functionalization is documented. Cyclotetramerization of enantioenriched axially chiral 2‐hydroxymethyl‐3‐naphthyl pyrroles under mild acidic conditions affords, after oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), the C 4 ‐symmetric α,α,α,α‐atropenantiomer as an only isolable diastereomer. Both regioisomeric Ir(Por*)(CO)(Cl) complexes catalyze the carbene C−H insertion reaction affording the same enantiomer, albeit with slight difference in enantioselectivity. With the optimum Ir‐complex 3 e , the 2‐substituted arylacetic acid derivatives were generated from diazo compounds and cyclohexadiene in excellent yields and enantioselectivities.