ChemInform Abstract: Isomerization of Allyl Ethers of Diols and Triols Catalyzed by Ruthenium Complexes.

Abstract

The allyl and propenyl ethers of diols and polyols have recently attracted increasing attention as monomers and comonomers [1–2]. Most convenient method of the preparation of propenyl ethers consists in isomerization of the corresponding, readily available allyl ethers. Moreover, this isomerization is a key step of deprotection of hydroxyl group, protected as allyl ether [3,4]. Particularly convenient catalysts of the isomerization of allyl to propenyl ethers are transition metal complexes. Complexes of ruthenium [5–8], rhodium [3,4], iridium [9], palladium [10], chromium [11], molybdenum [12], iron [13], platinum [14] and cobalt [15] were applied. In this communication, we describe the synthesis of propenyl ethers via isomerization of the corresponding allyl ethers of diols and triols catalyzed by [RuClH(CO)(PPh3)3] (Table). Other investigated ruthenium and rhodium complexes ([RuCl2(PPh3) 3], [ RuH 2(PPh3) 4], [ Ru(CO) 3(PPh3) 2], [ RhH(CO)(PPh 3) 3], [RuCl33H2O], [RhCl33H2O]) were less effective or even completely inactive. Quantitative yields of propenyl ethers were obtained only if a substrate contained neither triple bond nor allyl-hydroxyl group. Allyl ethers of 2-butyne-1,4-diol did not undergo isomerization to the corresponding propenyl ethers. It is likely that in this case stable acetylene complexes are formed: