ISSN:
1432-2234
Keywords:
Key words: Wolff rearrangement – [1,2]-hydrogen shift –β-Oxy-α-diazo carbonyl compounds – Density functional theory calculation – Laplacian distribution of the charge density
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract. The influence of protecting the hydroxyl group of a β-oxy-α-diazo carbonyl compound on the competition between the Wolff rearrangement (WR) and the [1,2]-hydrogen shift (HS) was investigated theoretically. Stationary points on the potential-energy surface were located with the B3LYP density functional and the 6-31G** basis set. For the basic system geometry optimisations at B3LYP/6-311+G** were performed to validate the reliability of the B3LYP/6-31G** calculations. Single-point energy calculations were carried out at the B3LYP/6-311+G** level on the B3LYP/6-31G**-optimised geometries. Further insight into the processes was achieved with the aid of the theory of “atoms in molecules” of Bader. The calculated energy barriers qualitatively predicted the yields of HS and WR obtained experimentally. In order to rationalise the calculated energy barriers, it was necessary to take into account not only the electronegativity of the protective groups but also the alignment of the migrating groups with the depletion sites at the carbene centre. Further, when the hydroxyl group was not protected the existence of an intramolecular hydrogen bond played an important role in both HS and WR.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002149900062
