[3 + 3]-Cycloaddition of α-Diazocarbonyl Compounds and N-Tosylaziridines: Synthesis of Polysubstituted 2H-1,4-Oxazines through Synergetic Catalysis of AgOTf/Cu(OAc)₂

Abstract

An impressive and new [3 + 3]-cycloaddition of α-diazocarbonyl compounds with N-tosylaziridines via synergetic catalysis of AgOTf and Cu­(OAc)2 has been well described, which offers efficient access to highly substituted 2H-1,4-oxazine derivatives. A variety of α-diazocarbonyl compounds and N-tosylaziridines were compatible substrates with convenient operations under mild reaction conditions.

Catalyst‐Free Electrophilic Ring Expansion of N‐Unprotected Aziridines with α‐Oxoketenes to Efficient Access 2‐Alkylidene‐1,3‐Oxazolidines

“…However, to the best of our knowledge, limited electrophilic ring expansions of them have been reported to date, [12,13] they are most transition‐metal‐catalyzed reactions [12] . The AgOTf and Cu(OAc) 2 synergetically catalyzed reaction of activated N ‐tosylaziridines and 2‐diazo‐1,3‐dicarbonyls generated 2 H ‐1,4‐oxazines (Scheme 1c) [14] . Recently, we realized the electrophilic ring opening of nonactivated aziridines for the direct and efficient synthesis of chiral tridentate ligands under neutral conditions [15] .…”

Tunable aziridinium ylide reactivity: non-covalent interactions enable divergent product outcomes

“…In this work, we describe our mechanistic findings to explain divergent reaction pathways from aziridinium ylides generated by leveraging ketone-containing carbenes, derived from Rh catalysis, to furnish fully substituted dehydromorpholines (Scheme 1D). [22][23][24] Both experimental and computational studies are presented that will inform future efforts of our and other groups' work on these fascinating and versatile reactive species.…”

Metal‐Catalyzed Cyclization: Synthesis of (Benzo)morpholines and (Benzo)[1,4]dihydrooxazines

“…Activated aziridines may also react with diazo compounds under metal catalysis. For example α‐diazo keto‐esters compounds such as 156 can react with sulfonyl‐aziridines 154 in the presence of Cu(OAc) 2 (10 mol‐%) and silver triflate (15 mol‐%) (Scheme ) . While the aziridine could be activated by the Lewis acid AgOTf to favor the open form 155 , the diazo compound can react with the copper salt to form a copper‐carbene 157 .…”