3-Borylbenzynes were generated in situ from 6-boryl-2-iodophenyl trifluoromethanesulfonates using i-PrMgCl·LiCl and applied to Diels–Alder reactions with substituted furans and pyrroles. The reactions allowed good functional group compatibility and produced the cycloadducts in high yields with high distal selectivities. Effective conversion of the boryl group of the products was achieved. A series
Synthetic studies toward diazonamide A. Preparation of the benzofuranone-indolyloxazole fragment
作者:Peter Wipf、Fumiaki Yokokawa
DOI:10.1016/s0040-4039(98)00231-7
日期:1998.4
benzofuranone-indolyloxazole fragment of the polycyclic marine natural product diazonamide A was prepared from tryptamine. The oxazole ring was synthesized from an α keto-indole via cyclodehydration with , and after selective Stille biaryl coupling with 2-iodo-6-stannylphenol, the benzofuranone ring was constructed by an intramolecular Heck annulation of an α,β-unsaturated aryl ester.