SnBr2-catalyzed highly selective synthesis of alkyl ethers from monoterpenes

Abstract

An efficient and Brønsted acid-free route to synthesize monoterpene ethers was developed using SnBr 2 as inexpensive and commercially affordable catalyst. This process consists of the synthesis of α-terpinyl alkyl ethers in SnBr 2-catalyzed reactions of β-pinene with alkyl alcohols. The catalytic activity of various tin(II) salts was assessed and compared to that of other homogeneous Lewis and Brønsted acids, in etherification reactions of β-pinene with methyl alcohol. SnBr 2 was the most active and selective catalyst toward α-terpinyl methyl ether. Tin(II) bromide is a water tolerant Lewis acid, which emerges as an efficient, simple, and cheap catalyst. The influence of the main reaction parameters was investigated, including SnBr 2 concentration, temperature and reaction time. Different alcohols and monoterpenes were also studied. The impact of the substrate nature on the reaction selectivity was assessed.

One-pot tandem synthesis of 5-ethoxymethylfurfural as a potential biofuel

“…The yields were lower for sterically hindered nucleophiles (alcohols), as already reported in the literature. 61–66…”