O. Itoh, Y. Ichikawa, Hiroaki Katano
May 1, 1976
Citations
0
Influential Citations
8
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
Cyclic orthoacetates of meso- and dl-2,4-pentanediol (cis- and trans-2-ethoxy-2,4,6-trimethyl-1,3-dioxane, 1) were prepared and characterized by NMR. The stereochemical courses of the reactions of 1 with water, hydrogen chloride, trityl chloride, and acetic acid were investigated. The reactions with water gave 4-acetoxy-2-pentanol (4) with complete retention of configuration, while those with the other reagents gave 4-acetoxy-2-chloropentane (3) and 2,4-diacetoxypentane with complete inversion. Acetolyses of 3 and the tosylate of 4 gave 2,4-diacetoxypentane predominantly with retention in the absence of water. Hydrolysis of the tosylate gave 4 with almost complete inversion. These results can be explained by the mechanism that the reactions proceed mainly through acetoxonium cation intermediate involving six-membered ring. The fluoroborate salt of this acetoxonium cation was prepared and characterized by NMR.