Jeffery’s phase-transfer catalysis conditions

Similar to the Pd-catalyzed pyrrole and thiophene annulations, an intramolecular Heck reaction of substrate 91 resulted in benzofuran 92 [80], Such an approach has become a popular means of synthesizing fused furans. Muratake et al. exploited the intramolecular Heck cyclization to establish the tricyclic core structure en route to the synthesis of a furan analog of duocarmycin SA, a potent cytotoxic antibiotic [81]. Under Jeffery s phase-transfer catalysis conditions, substrate 93 was converted to tricyclic derivatives 94 and 95 as an inseparable mixture (ca. 4 1) of two double bond isomers. 

In the synthesis of the -azaebumane series, an intramolecular heteroaryl Heck reaction was the major operation to realize the cyclization <95TL1491>. Under Jeffery s phase-transfer catalysis conditions, the -azaebumane skeleton 105 was prepared from bromopyridine 104. The migratory insertion occurs onto the C(2) position of the indole ring. 

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See also in sourсe #XX -- [ ]

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