Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

Solvents are crucial platforms in organic synthesis. Thereby, the choice of a solvent is critical in order to develop sustainable eco-friendly synthetic methodologies. Hence, the present consensus is to employ environmentally friendly solvents which have broad applications in fine chemical syntheses, especially from the context of large-scale industrial preparations. In this review, we provide several examples for the utilization of 2-MeTHF, CPME, and 4-MeTHP in several organic reactions pertaining to organometallic-, organo-, and biocatalysis and highlight their potential use as benign alternatives to conventional ether solvents. These solvents have favorable physical and chemical characteristics, such as low toxicity and high chemical and thermal stabilities, which make them promising media for a large breadth of synthetic chemistry and triggers development of reactions with green chemistry protocols.