ChemInform Abstract: Regioselective Preparation of 2,4‐, 3,4‐, and 2,3,4‐Substituted Furan Rings. Part 1. [1,4] O→C and [1,4] C→O Silyl Migrations of Silyl Ethers and Esters Attached to Furan and Thiophene Rings.

Abstract

Regioselective Preparation of 2,4-, 3,4-, and 2,3,4-Substituted Furan Rings. Part 1. [1,4] O→C and [1,4] C→O Silyl Migrations of Silyl Ethers and Esters Attached to Furan and Thiophene Rings.-A variety of furan-and thiophene-based silyl ethers and silyl esters undergo the title rearrangement in good to excellent yields if the silane contains bulky substituents. The reaction is shown by crossover studies to proceed via an intramolecular O→C silyl migration. This migration is shown to be reversible and proceeds via intramolecular C→O silyl migration. Secondary alcohols like (XIII) give also C→O migration products. -(BURES, E.; SPINAZZE, P. G.; BEESE, G.; HUNT, I. R.; ROGERS, C.; KEAY, B. A.; J. Org. Chem. 62 (1997) 25, 8741-8749; Dep. Chem., Univ. Calgary, Calgary, Alberta T2N 1N4, Can.; EN)