Practical and Scalable Synthesis of 7-Azetidin-1-yl-4-(hydroxy­methyl)coumarin: An Improved Photoremovable Group

Abstract

7-Substituted 4-methylcoumarin derivatives are widely employed as photoprotecting groups in chemistry and biology. We have recently shown that the 7-azetidinylated version of this photocage releases carboxylic acids in aqueous solution more efficiently than the traditionally used 7-diethylamino variant. Here we present a robust and scalable route to prepare the 7-azetidinylated alcohol, a useful precursor for the photoprotection of a variety of leaving groups, and its use in the preparation of model phosphate, sulfonate, and carbamate derivatives.