Fischer indole synthesis - Wikipedia

Using chemistry developed at by Stephen Buchwald, the Fischer indolesynthesis can be completed using aryl bromides as startingmaterials. Notethat this also gives evidence to the fact that hydrazones arepotential intermediates in the classical Fischer indolesynthesis.

A Convenient Modification of the Fischer Indole Synthesis with a Solid Acid.
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Type 1 synthesis (-) involves aromatic C–H functionalization. Although C–H activation is thought of as a modern topic, the venerable Fischer indole synthesis (still under active development, -) falls under this heading. Paul R. Brodfuehrer and Shaopeng Wang of Bristol-Myers Squibb described the convenient () reaction of an aryl hydrazine 1 with dihydropyran 2 to give the 3-hydroxypropylindole 3. Stephen L. Buchwald of MIT developed an elegant () amination of aryl iodides to give Boc-protected aryl hydrazines, such as 4. Acid-mediated condensation of 4 with the ketone 5 delivered the indole 6. The condensation of 4 and 5 proceeded with high regioselectivity. Norio Takamura of Musashino University, Tokyo presented a complementary approach (), the addition of an aryllithium 8 to an α-diazo ester 7, followed by acid-mediated cyclization. The ester of 9 is easily manipulated, and can also be removed altogether. Several other useful variations on the Fischer indole synthesis have been reported.-


Fischer Indole Synthesis - Organic chemistry

Fancy drug candidates: The first preparation of indoloparacyclophanes is reported through the use of the Buchwald variant of the Fischer indole synthesis (see scheme).
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