Ruthenium-Catalyzed Hydroarylations of Oxa- and Azabicyclic Alkenes

Abstract

A ruthenium-catalyzed arylation reaction of oxa-and azabicyclic alkenes with (hetero)arenes by C−H bond activation has been discovered. The reaction does not require additives and utilizes dioxygen in realizing the catalytic cycle leading to monosubstituted 7-oxa and 7-azabenzonorbornane derivatives.

Combination of Cp*RhIII‐Catalyzed C−H Activation and a Wagner–Meerwein‐Type Rearrangement

“…[6] On the basis of these observations and previous reports, [5] aplausible catalytic cycle is shown in Scheme 4. [6] On the basis of these observations and previous reports, [5] aplausible catalytic cycle is shown in Scheme 4.…”

“…[5] On the basis of these considerations,w ef avor Path aw ith aR h III -Rh V -Rh III process as am echanistic model for our current reaction as an electron-deficient metal center is more likely to induce the Wagner-Meerwein-type rearrangement. Moreover, the C À Rh III bond is an ucleophilic species and belimination or protonation of B could occur as was reported.…”

“…[1] Specifically,C p*Rh III -catalyzed CÀHa ctivation/coupling reactions have been widely explored and enabled the development of methods for the synthesis of various structurally diverse organic molecules. [3][4][5] Both b-elimination and protonation of the resulting CÀRh bond have been well studied in Cp*Rh III -catalyzed CÀHa ctivation, giving ring-opened and protonated products,r espectively (Scheme 1a;C p* = h-C 5 Me 5 ). [3][4][5] Both b-elimination and protonation of the resulting CÀRh bond have been well studied in Cp*Rh III -catalyzed CÀHa ctivation, giving ring-opened and protonated products,r espectively (Scheme 1a;C p* = h-C 5 Me 5 ).…”

“…[6] In connection with the advantages of Cp*Rh III -catalyzed CÀHf unctionalization [2] and the knowledge that the Rh III ÀCb ond generated by CÀHa ctivation could add to the C=Cb ond of 7-oxa/azabenzonorbornadienes,which was pioneered by Li, [5] it would be attractive to utilize this C À Ha ctivated species in aW agner-Meerweintype rearrangement using norbornadiene derivatives (Scheme 1b). [6] In connection with the advantages of Cp*Rh III -catalyzed CÀHf unctionalization [2] and the knowledge that the Rh III ÀCb ond generated by CÀHa ctivation could add to the C=Cb ond of 7-oxa/azabenzonorbornadienes,which was pioneered by Li, [5] it would be attractive to utilize this C À Ha ctivated species in aW agner-Meerweintype rearrangement using norbornadiene derivatives (Scheme 1b).…”

Jenseits von Friedel und Crafts: dirigierte Alkylierung von C‐H‐Bindungen in Arenen

“…Aufsätze kylierung.M ethylencyclopropane kçnnen rutheniumkatalysiert ebenfalls als Alkylierungsreagentien eingesetzt werden, [163] wodurch lineare Produkte ebenso wie oxa-und azabicyclische Alkene zur Verfügung gestellt werden; [164] außerdem wurde die Effizienz eines Ruthenium/NHC-Systems demonstriert. [165] Thiophen- [162] und Benzofuranderivate [166] erwiesen sich als geeignete Substrate füre ine große Bandbreite zu alkylierender Arene.…”