Cobalt‐Catalyzed Diastereoselective [4+2] Annulation of Phosphinamides with Heterobicyclic Alkenes at Room Temperature

Abstract

Cobalt‐catalyzed sp2 C−H bond functionalization of diarylphosphinamides with heterobicyclic alkenes was demonstrated at room temperature employing commercially available cobalt(II)‐salts. The effectiveness of this strategy was illustrated with the reaction of various 8‐aminoquinoline derived phosphinic amides and 7‐oxa/azabenzonorbornadienes. The reaction conditions exhibited excellent functional group tolerance and high diastereoselectivities. Furthermore, extension of this approach to the preparation of polyaryl cyclic phosphinamides was achieved through the dehydrative ring opening/aromatization sequence.magnified image

Recent Advances in Transition-Metal-Catalyzed C–H Functionalization Reactions Involving Aza/Oxabicyclic Alkenes

“…25c Scheme 23 Annulations of N-methoxybenzamides 42 with 7-oxabenzonorbornadiene (2) 25a Volla's group has also reported an annulation reaction of diphenylphosphinamides 44 with the readily available bicyclic olefin 2 using Co(acac) 2 as the catalyst, Mn(OAc) 3 •2H 2 O as the oxidant, and NaOPiv as the base (Scheme 24). 26 It was found that the formed annulation products 45a-m were the thermodynamically more favorable exo-isomers, as confirmed by single-crystal XRD studies. This methodology shows compatibility with differently substituted phoshinamides and bicyclic olefins, resulting in the desired substituted products in moderate to good yields.…”

Rhenium(I)‐Catalyzed ortho‐C−H Addition to Bicyclic Alkenes

“…Our group first exploits this 7‐oxabenzonorbornadienes substrates in Co‐catalyzed bidentated directed C−H functionalizations reactions to give indenones via [3+2] annulation strategy . Followed by this report, Volla and his group synthesized the bridged polycyclic phosphinamides from the reaction of phosphonamides and 7‐oxa/azabenzonorbornadienes under Co III catalytic system . During the preparation of this manuscript, Chatani et al.…”

“…[6g] Followed by this report, Volla andh is group synthesized the bridged polycyclic phosphinamides from the reaction of phosphonamides and 7-oxa/azabenzonorbornadienes under Co III catalytic system. [12] During the preparation of this manuscript, Chatani 5 Br NaOAc (30) toluene -3Re(CO) 5 Br NaOAc (30) tert-butyltoluene 18 4Re(CO) 5 Br NaOAc (30) o-xylene-5Re(CO) 5 Br NaOAc (30) 1,4-dioxane 92 6Re(CO) 5 Br KOAc(30) 1,4-dioxane -7Re(CO) 5 Br…”

Deoxygenative C2-heteroarylation of quinoline N-oxides: facile access to α-triazolylquinolines

“…In spite of the above methods for the C2-amination, the establishment of a simple, efficient and atom-economical method for the synthesis of 2-triazolylquinoline derivatives is highly desired. The continuous interest and efforts of our group for the derivatization of quinoline moieties [57] and use of N-sulfonyl-1,2,3-triazoles as heterocyclic precursors encouraged us to develop a new strategy for the regioselective C2-triazolylation of quinoline N-oxide under mild reaction conditions (Scheme 1b) [58][59][60][61][62].…”