Cadogan synthesis

T. Kauffmann, Angew. Chem., Int. Ed. Engl. 13, 627-639 (1974). Syntheses from phosphite reduction of aromatic nitro compounds J. I. G. Cadogan, Synthesis pp. 11-16 (1969). 

Example 8 Synthesis of 2,7-Dibromocarbazole with Triethyl Phosphite (Cadogan Synthesis)... 

Burger, K In Organophosphorus Reagents in Organic Synthesis, Cadogan, J I G., Ed, Academic London, 1979, p 492 and literature cited therein... 

For a review, see Rowley, A.G. in Cadogan Organophosphorus Reagents in Organic Synthesis Academic Press NY, 1979, p. 295. 

Timari et al. described a total synthesis of furostifoline (224) starting from commercial o-cresol (1133). The key steps in this approach are the Suzuki coupling to the o-nitrobiaryl 1139 and subsequent Cadogan s reductive cyclization via a nitrene intermediate (692). 

Five years later, the same authors reported an improved total synthesis of arcyriaflavin A (345) starting from the TBS enol ether 1490 (for the synthesis see Scheme 5.252). This route involves two indolizations based on silyl enol ether nucleophilic attack and Fischer processes. Using Cadogan s procedure by heating in triethyl phosphite, the TBS enol ether 1490 was transformed into the ketone ( + )-1495, involving silyl enol ether-mediated indolization. Finally, Fischer indolization of (+ )-1495 by reacting with phenylhydrazine (524) led directly to arcyriaflavin A (345) in 57% yield (794) (Scheme 5.253). 

Mullen et al. reported an efficient, two-step synthesis of 2,7-dibromocarbazole (388) starting from 4,4 -dibromobiphenyl (1566). This method uses Cadogan s... 

B-79MI51603 J. I. G. Cadogan in Organophosphorus Reagents in Organic Synthesis , ed. J. 

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