Iridium/copper-cocatalyzed asymmetric ring opening reaction of azabenzonorbornadienes with amines

Abstract

A combination of iridium/copper associated with (R)-Difluorphos catalyst for the asymmetric ring opening reaction of azabenzonorbornadienes with amines was developed, which afforded chiral trans-vicinal diamines in 80-97% yields with 93-95% enantioselectivities.

Palladium Catalyzed Tandem Reaction of Oxabenzonorbornadienes with Anhydrides

“…In our previous Pd‐catalyzed ARO reactions of oxabenzonorbornadienes with alcohols, the products with trans ‐configuration were obtained. [13g] So we are proposing that the addition of the third molecule will follow the same pathway and the remaining part being same as the dimer. The NMR spectroscopic data of the trimer was also analyzed.…”

“…Some other reagents which have been successfully used as nucleophiles in the ARO reaction of aza‐/oxabenzonorbornadienes are amines, phenols, organozinc, lithium, Grignard, aluminium and boron reagents,[2f], etc. Our group has been involved in the asymmetric reactions of bicyclic alkenes and we have succeeded in developing new transition metal/Lewis acid co‐catalytic systems for the asymmetric ring‐opening reaction of aza/oxabicyclic alkenes . Recently we have reported the successful application of anhydrides as nucleophiles in the ARO reaction of oxabenzonorbornadienes under the catalytic system of Rh(COD) 2 BF 4 and ( R , S )‐PPF‐P t Bu 2 (Scheme a).…”

“…The ARO products were obtained in good yields (up to 94 % yield) and high enantioselectivities (up to 95 % ee ). [13f]…”

Transition Metal/Lewis Acid Co‐Catalyzed Ring‐Opening Reactions of Oxa/Azabenzonorbornadienes

“…The reaction was co-catalyzed by iridium and copper giving the chiral transvicinal diamines in 80-97 % yields with up to 95 %ee. [44] The study revealed that the Lewis acid played an important role in the reaction as there was a significant increase in both the yield and the enantioselectivity when Lewis acid CuBr was added in the reaction. This provided a useful method for the synthesis of chiral vicinal diamines which are important structural motifs in natural products and biologically active compounds.…”

“…Our group has developed a method for the ring‐opening reaction of azabenzonorbornadienes with amines. The reaction was co‐catalyzed by iridium and copper giving the chiral trans ‐vicinal diamines in 80‐97 % yields with up to 95 % ee . The study revealed that the Lewis acid played an important role in the reaction as there was a significant increase in both the yield and the enantioselectivity when Lewis acid CuBr was added in the reaction.…”