Alcohol-Incorporating Diels–Alder Dimerization ofIn SituFormedortho-Quinamine via Co-Nitrenoid Insertion

Abstract

We disclose herein a Cp*Co(III)(LX)-catalyzed dearomative Diels−Alder dimerization of 2,6-disubstituted phenyl azidoformates. Upon the postulated cobalt-nitrenoid insertion into the neighboring ortho-carbon, the key intermediate of ortho-quinamine was generated for the subsequent dimeric cycloaddition process. A series of experimental and computational studies suggested that the quinolinol ligand of the cobalt catalyst plays a crucial role in the alcoholic solvent incorporation into the o-quinamine moiety, thereby enabling the Diels− Alder dimerization to furnish the bridged tricyclic bisamidation products.

Versatile Utility of Cp*Co(III) Catalysts in C–H Amination under Inner- and Outer-Sphere Pathway

“…While nonafluoro-tert-butanol (NFTB) solvent was effective for the above-mentioned amidative alkyl migration, the use of hexafluoro-isopropanol (HFIP) as solvent completely changed the chemical reactivity (Scheme 18). 43 In HFIP solvent system, subjecting 2,6-dimethyl phenyl azidoformate to the identical Co1 catalytic conditions afforded HFIP-incorporated bisamidated endo-cyclodimers resulting from Diels-Alder dimerization. Interestingly, additional alkyl alcohols could also be introduced into the dimeric Diels-Alder scaffold when they were used in a co-solvent system containing NFTB.…”

Chiral self-recognition in a bispericyclic cyclodimerisation reaction of 1-azadienes

“…12 An elegant example of bispericyclic Diels–Alder dimerisation is the [4 + 2] cyclodimerisation of ortho -quinols, applied for the synthesis of diverse natural products. 13 As in nature in several hundred species of fish, angiosperms or invertebrate animals, experiencing life both as a male and as a female is the reproductive norm, 14 we can consider bispericyclic reactions as a kind of “hermaphroditism of molecules”.…”