PPh₃‐Catalyzed Ring‐Expansion Reactions of Sulfamate‐Derived Cyclic Imines with Acetylenedicarboxylates

Abstract

The PPh3-catalyzed ring-expansion reaction of sulfamate-derived cyclic imines with acetylenedicarboxylates has been developed. The reaction works quite efficiently under very mild conditions to afford benzo[g][1,2,3]oxathiazocine-4,5-dicarboxylate 2,2-dioxide derivatives in high yields.

Phosphine Organocatalysis

“…Interestingly, the expected dihydroazetes underwent formal retro-[2 + 2] ring opening to give functionalized benzo[ g ][1,2,3]oxathiazocines (Scheme 464). 538 The reaction is highly efficient, tolerating cyclic imines with various substitution patterns.…”

Rhodium‐Catalyzed Cycloisomerization of 2‐Alkynyl‐N′‐arylidenebenzohydrazides through exo‐Carboamination

“…Carboamination of alkynes with imines, involving the cleavage of an imine C=N bond forming a new 1‐aza‐1,3‐diene moiety, can be considered as a formal C≡C/C=N metathesis (Scheme (a)) . The reaction occurs thermally or in the presence of catalysts .…”

“…Carboamination of alkynes with imines, involving the cleavage of an imine C=N bond forming a new 1‐aza‐1,3‐diene moiety, can be considered as a formal C≡C/C=N metathesis (Scheme (a)) . The reaction occurs thermally or in the presence of catalysts . Catalysts that promote alkyne–imine coupling reactions include phosphines, group 4 metals, gold(I), and Brønsted and Lewis acids .…”

“…The reaction occurs thermally or in the presence of catalysts . Catalysts that promote alkyne–imine coupling reactions include phosphines, group 4 metals, gold(I), and Brønsted and Lewis acids . For intramolecular carboamination, there have been reports on endo ‐rearrangement reactions catalyzed by gold(I) complexes; however, the corresponding exo ‐rearrangement has not been documented (Scheme (b)).…”

Phosphine‐Catalyzed Diastereoselective [3 + 3] Annulation of Morita–Baylis–Hillman Carbonates with C,N‐Cyclic Azomethine Imines

“…During the past two decades, nucleophilic phosphine‐catalyzed annulation reactions have been developed as one of the reliable and useful tools for synthesis of various biologically important carbocyclic and heterocyclic compounds and total synthesis of natural products . Under phosphine catalysis conditions, a variety of annulation reactions such as [2 + 2] , [2 + 2 + 1] , [3 + 2] , [4 + 1] , [2 + 2 + 2] , [3 + 3] , [4 + 2] , [4 + 3] , [3 + 2 + 3] , [6 + 3] , and [8 + 2] annulations have been achieved . Among these annulation reactions, phosphine‐catalyzed [3 + 3] annulation reaction has less been investigated, and only a few successful examples were reported , although this type of reactions could serve as a very useful tool for constructing biologically significant six‐membered heterocyclic skeletons.…”