A copper-catalyzed
cascade reaction of diazo compounds with 1,n-allenynes
(n = 6,7) was reported, which
provides efficient access to various functionalized 3-azabicyclo[m.2.0] frameworks (m = 5,6) in moderate
to excellent yields under mild reaction conditions. The reaction proceeds
through intermolecular cross-coupling to form bisallene intermediates,
followed by subsequent intramolecular [2+2] cycloaddition.
The
reaction of vinylsulfonamides with donor–acceptor carbenes
derived from α-aryldiazoesters, catalyzed by the tert-butyl glycine-derived dirhodium complex Rh2(S-4-Br-NTTL)4, has been reported. This method provides
a variety of α-aryl-β-aminocyclopropane carboxylic acid
derivatives bearing one quaternary carbon stereogenic center vicinal
to the amino-substituted carbon in high yields with excellent diastereo-
and enantioselectivities. Vinylsulfonamides showed complementary advantages
over the well-developed vinylamides or vinylcarbamates for this Rh(II)-catalyzed
cyclopropanation strategy. Moreover, these conformationally restricted
α-aryl-β-aminocyclopropyl carboxylic acid derivatives
can be readily incorporated into dipeptides.
Reported herein are the unprecedented copper-catalyzed formal [n + 1]/[n + 3] (n = 5, 6) cycloadditions of diazo compounds with imidazolidines/hexahydropyrimidines, thus providing a general, economical, and efficient route to construct different sized (six-to nine-membered) diaza-heterocycles in moderate to excellent yields under mild reaction conditions. This strategy features the use of copper catalyst to accomplish such diverse annulations and the utilization of imidazolidines/ hexahydropyrimidines as stable 1,5-/1,6-dipoles.
This short review summarizes the most recent developments (since 2010) in the tandem cyclization/cycloaddition of allene intermediates, generated from the copper-catalyzed cross-coupling of diazo compounds with terminal alkynes, to afford cyclic compounds.1 Introduction2 Cyclization2.1 Cyclization with Nucleophiles2.2 Cyclization with Electrophiles2.3 6π-Electrocyclization2.4 Other Cyclization3 Cycloaddition4 Conclusion
A copper‐catalyzed tandem intermolecular ylide formation/intramolecular cycloaddition of diazo compounds and aldehyde‐tethered‐cyclohexadienones was reported, chemo‐ and diastereoselectively providing oxapolycyclic frameworks in moderate to excellent yields under mild conditions. This reaction creates two C−C bonds and one C−O bond with five stereocentres including two all‐carbon quaternary centres. Moreover, the late‐stage diversification of products can be realized via chemoselective substitutions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.