The Development of a New Nitrating Agent: The Unusual Regioselective Nitration of Diphenylpolyethylene Glycols and Phenylpolyethylene Glycols with Trimethylsilyl Nitrate - BF3OEt2

Article abstract of DOI:10.1021/jo00303a024

We have investigated the nitration of the following podands, 1-phenoxy-8-(2'-nitrophenoxy)-, 1-phenoxy-8-(4'-nitrophenoxy)-, and 1-(2',4'-dinitrophenoxy)-8-phenoxy-3,6-dioxaoctane (2, 3, and 4), and 1-(2',4'-dinitrophenoxy)-11-phenoxy-3,6,9-trioxaundecane (5), 1-phenoxy-3,6,9-trioxadecane (6), and 1-phenoxy-3,6,9,12-tetraoxatridecane (7), with trimethylsilyl nitrate catalyzed by BF3OEt2, which is soluble in nonpolar solvents.The reaction selectivity was measured by the ortho:para ratio of the nitrated products and was unusually large in CCl4.The structures of all isolated products, 1,8-bis(2'-nitrophenoxy)-, 1-(2'-nitrophenoxy)-8-(4'-nitrophenoxy)-, 1,8-bis(4'-nitrophenoxy)-, 1-(2',4'-dinitrophenoxy)-8-(2'-nitrophenoxy)-, and 1-(2',4'-dinitrophenoxy)-8-(4'-nitrophenoxy)-3,6-dioxaoctane (8, 9, 10, 11, and 12), 1-(2',4'-dinitrophenoxy)-11-(2'-nitrophenoxy)- and 1-(2',4'-dinitrophenoxy)-11-(4'-nitrophenoxy)-3,6,9-trioxaundecane (13 and 14), 1-(2'-nitrophenoxy)- and 1-(4'-nitrophenoxy)-3,6,9-trioxadecane (15 and 16), and 1-(2'-nitrophenoxy)- and 1-(4'-nitrophenoxy)-3,6,9,12-tetraoxatridecane (17 and 18), were confirmed by the independent preparation of these compounds using a modification of Joeger's method.We have invented a new nitrating system (trimethylsilyl nitrate and BF3OEt2) and have shown that the selectivity (o/p ratio of nitrated products) is unusually high in CCl4.