Metal-free new synthesis of 1,3-naphthoxazines via intramolecular cross dehydrogenative-coupling reaction of 1-(α-aminoalkyl)-2-naphthols using hypervalent iodine(III) reagent

Latest Advancements in Transition‐Metal‐Free Carbon‐Heteroatom Bond Formation Reactions via Cross‐ Dehydrogenative Coupling

“…Waghmode et al . demonstrated the similar intramolecular C−O bond formation through CDC of 1‐( α aminoalkyl)‐2‐naphthols [61] …”

“…The reductive elimination of C generated the iminium cation D which got trapped intramolecularly by the phenoxide ion to afford the desired product (Scheme 65). [61] …”

“…Waghmode et al demonstrated the similar intramolecular CÀ O bond formation through CDC of 1-(α aminoalkyl)-2naphthols. [61] The reaction occurred under extremely mild conditions using PhI(OAc) 2 (diacetoxyiodo benzene) in DCM at room temperature. It was found that both electron releasing and withdrawing groups were well tolerated and did not show much difference in the reactivity (Scheme 64).…”

Metal‐Free Cross‐Dehydrogenative Coupling (CDC): Molecular Iodine as a Versatile Catalyst/Reagent for CDC Reactions

“…Hypervalent iodine (I 3 + )r eagents [9][10][11][12] have been proved to be effective alternatives for TMs, and many excellent results have been achieved by use of I 3 + reagents (PhIX 2 ). However,l arge amountso fi odobenzene are generated as ab yproduct during hypervalent-iodine-catalyzed CDC reactions.…”

“…Thus, TM‐free CDC reactions have attracted prominent attention in recent times, as they avoid expensive TM catalysts and the challenges involved in the removal of toxic metal residues from the desired products. Hypervalent iodine (I 3+ ) reagents have been proved to be effective alternatives for TMs, and many excellent results have been achieved by use of I 3+ reagents (PhIX 2 ). However, large amounts of iodobenzene are generated as a byproduct during hypervalent‐iodine‐catalyzed CDC reactions.…”