Aziridines Friedel-Crafts reaction

The FeCls-catalyzed Friedel-Crafts reactions of electron-rich arenes with imines or aziridines provide a facile and convenient route for the synthesis of p-aryl... 

Typically in ring-opening reactions of aziridines, the amine functional group is retained in the product molecule. An example of such a reaction where the amine group has been lost has recently been reported <06TL977>. An intramolecular Friedel-Craft reaction of aziridine 91 leads to the expected product as an intermediate. Under the rather drastic reaction conditions, the sulfonamide is lost leading to formation of the naphthalene ring. 

Scheme 52 Mechanism of the Friedel-Crafts reaction of enamides and indoles 2.4.2 Aziridines...

Friedel- Crafts reactions. Benzyl ethers are activated by FeCls to react with arenes to provide diarylmethanes. A-Tosyhmines and aziridines also become electrophilic toward electron-rich arenes. ... 

Thioacetals eliminate to vinylsulfides in the presence of CuOTf (Scheme 46).192 Cu1 and Cu11 triflates are mild Lewis acids for Friedel-Crafts acylation and alkylation reactions. CuOTf effectively catalyzes the reaction of anisole with selenoesters.193,194 Copper(II) sulfate promotes epoxide ring opening reactions in the presence of pyridine,195 with retention of configuration being observed. Cu(OTf)2 is a catalyst for the ring opening of aziridine by aniline.196... 

Enantioselective vanadium and niobium catalysts provide chemists with new and powerful tools for the efficient preparation of optically active molecules. Over the past few decades, the use of vanadium and niobium catalysts has been extended to a variety of different and complementaiy asymmetric reactions. These reactions include cyanide additions, oxidative coupling of 2-naphthols, Friedel-Crafts-type reactions, pinacol couplings, Diels-Alder reactions, Mannich-type reactions, desymmetrisation of epoxides and aziridines, hydroaminations, hydroaminoalkylations, sulfoxida-tions, epoxidations, and oxidation of a-hydroxy carbo) lates Thus, their major applications are in Lewis acid-based chemistiy and redox chemistry. In particular, vanadium is attractive as a metal catalyst in organic synthesis because of its natural abundance as well as its relatively low toxicity and moisture sensitivity compared with other metals. The fact that vanadium is present in nature in equal abundance to zinc (albeit in a more widely distributed form and more difficult to access) is not widely appreciated. Inspired by the activation of substrates in nature [e.g. bromoperoxidase. 

Carbon-based nucleophiles continue to be examined in ring-opening reactions of aziridines. Select examples from the year 2014 include employment of indole derivatives in Friedel-Crafts-type reactions (14T4512, 14MI16478), utilization of malonate-type nucleophiles (14JA9190, 14EJ0767), and arylation reactions involving the use of N-heterocyclic... 

---