Ab Initioand Semiempirical Studies on the Transition Structure of the Baeyer and Villiger Rearrangement. The Reaction of Acetone with Performic Acid

Abstract

Ab initio and semiempirical calculations have been performed on the reaction mechanism of the Baeyer−Villiger reaction of acetone and performic acid. They focus, at the rate-limiting step (RLS), on the structures, energies, Mulliken charges, and what we refer to as evolution of the bond orders. The geometries of the Criegee intermediate, the methyl group migration transition state structure (TSs), and the product were found and optimized with the HF/ 4-21G, the HF/4-31G, and the HF/6-31G** basis sets of double-ζ quality in the ab initio methodology. AM1, PM3, and MNDO were used in the semiempirical calculations. The correlation energies were also evaluated at the MP2/6-31G**//HF/4-31G and MP2/6-31G** level of theory. A discussion dealing with the nature of the transition state structure (TSs) and its determination is presented, observing that irrespective of the method of calculation, the topology of the TSs and the general orientation of the transition vectors are invariant. From the calculations in vacuo, by using novel methodology, we find two reactive cycles: a central one, where the oxygen bonds break in close synchronicity with the methyl group migration, and a secondary one, where a proton is transferred. This proton seems to have protected the carbonyl oxygen from the attack of the methyl group. Scanning the movement of the proton, we can observe the effect that it produces on the atoms belonging to the reactive cycles and, interestingly, the lack of effect on those that do not belong to it. Finally, by using elliptic coordinates, we see that the atoms constituting both of the reactive cycles are found on ellipsoidal surfaces where the reactive centers are the foci.

Substituent Effects in the Migration Step of the Baeyer−Villiger Rearrangement. A Theoretical Study

“…[35][36][37][38][39][40] Our results agree with this observation, considering that this intermediate displays C 13 22 Overall, the breaking of the C 2 -C 13 bond is much more susceptible to substitution than the formation of the C 13 -O 7 bond; see Table 1. The calculated data show that the electron-withdrawing groups cause lengthening of the C 2 -C 13 bond with the exception of the p-Cl derivative, whereas the electron-donor groups induce a contrary effect, according to the observed 14 C isotope effect.…”

“…22 In this case, the DFT calculations describe the TS in a slightly more The HOMO corresponds to the acid fragment, so the value is given for the next highest occupied molecular orbital (HOMO -1) which is mainly located on the ester moiety. advanced stage for the aryl transfer than the Hartree-Fock method.…”

“…This is in agreement with the explanation proposed by Ogata and Sawaki, in which the p-OCH 3 group induces a change of the BV mechanism, as quoted already. 11 In our first study of this reaction using a simple model (performic acid and acetone), 22 we showed that the transitionstate (TS) geometry associated with the BV rearrangement and the general orientation of the transition vectors are nearly invariant of the calculation method. More recently, 23 we used this finding to analyze the migration step on the BV reaction of acetone with some alkyl and aryl peracids by using AM1 and PM3 methods.…”

100 Years of Baeyer–Villiger Oxidations

“…This acid the rearrangement. [100] Metal-catalyzed BaeyerϪVilliger oxidations have been recently reviewed by Strukul [101] (the had also been shown to protonate all investigated substituted benzophenones. Consequently, the rate of the ad-work of Bolm [102] on the asymmetric version with a chiral Cu complex has been discussed in this review).…”

Preparation of TADOOH, a Hydroperoxide from TADDOL, and Use in Highly Enantioface- and Enantiomer-Differentiating Oxidations

“…5). 23 ) For calculations of the transition-state structure of the Baeyer-Villiger rearrangement of acetone with performic acid, see[53] 24. ) For rearrangement of the neutral Criegee adducts A and B, much higher free energies (!…”