An environmentally benign synthesis of allyl ethers has been developed which can be applied to a highly chemoselective protection of hydroxyl groups. A highly efficient [CpRu]–2‐quinolinecarboxylic acid (L) catalytic system was successfully employed for the dehydrative allylation of various alcohols without additional activators and solvent (see scheme; R=alkyl, aryl, multifunctional alkyl, Cp=C5H5).

A cationic CpRu(II) complex in combination with quinaldic acid shows high reactivity and chemoselectivity for the catalytic deprotection of hydroxyl groups protected as allyl ethers. The catalyst operates in alcoholic solvents without the need for any additional nucleophiles, satisfying the practical requirements of operational simplicity, safety, and environmental friendliness. The wide applicability of this deprotection strategy to a variety of multifunctional molecules, including peptides and nucleosides, may provide new opportunities in protective group chemistry. [structure: see text]

Graphical abstract

A facile and efficient method for the quantitative synthesis of [CpRu(IV)(p-C 3 H 5 )(2-quinolinecarboxylato)]PF 6 from [CpRu(CH 3 CN) 3 ]PF 6 , 2-quinolinecarboxylic acid, and 2-propen-1-ol has been established. The cationic Ru(IV) complex is air-and moisture-stable, and can be stored in a vial for at least six months. This complex realizes a simple and easy operation for both the deallylation of allyl ethers in methanol and the dehydrative allylation of alcohols. Furthermore, with removal of the volatile allyl methyl ether co-product from the reaction system, the robust catalyst can attain a turnover of 10000 cycles of allyl ether cleavage.