How does the OH group affect the conversion of carbonyl oxide to dioxirane?

The effects of the hydroxy group on the conversion of carbonyl oxide to dio xirane have been examined in the gas phase and in solution with B3LYP/6-31G (d,p). The solvent has been modeled with the SCIPCM method. All the possibl e orientations of the hydroxy group (syn-in, syn-out, anti-in, anti-out) on carbonyl oxide and dioxirane tin, out) have been considered. The Si (syn-i n) conformer of hydroxy carbonyl oxide was not located as a stationary stru cture, instead peroxyformic acid is formed. The isomerization barrier for S -o is found to be twice as large as the one for the A, and Ai in vacuum and in a polar media (epsilon = 78.5). Single point calculations with B3LYP/6- 311 + G(3df,2p)//B3LYP16-31G(d,p) mimic the same trend. (C) 2000 Elsevier S cience B.V. All rights reserved.