Dyotropic Reactions: Mechanisms and Synthetic Applications

Abstract

Israel Ferna ´ndez (Madrid, 1977) enjoyed studying chemistry at the Universidad Complutense of Madrid (UCM). In 2005, he earned his Ph.D. in Chemistry at the UCM under the supervision of Prof. Miguel A. Sierra and received the Prize for the best Doctoral Thesis in Synthetic Chemistry by the Spanish Royal Society of Chemistry and the Lilly-Young Researcher Prize. After that, he joined the Theoretical and Computational Chemistry group of Prof. G. Frenking at the Philipps Universita ¨t Marburg as a postdoctoral researcher studying the bonding situation and reaction mechanisms of organic and organometallic compounds. At the present, I.F. is a Ramo ´n y Cajal fellow at the UCM. His current research includes the computational study of the bonding situation and reaction mechanisms of organic, organometallic, and bioorganic compounds with special interest in C-C bond forming processes.

Isomerisation of CF2ClCH2Cl and CFCl2CH2F by Interchange of Cl and F Atoms with Analysis of the Unimolecular Reactions of Both Molecules

“…The slope corresponds to 2.12 torr. The bath gas was SF 6 for the D/S measurements and the analysis was by GC-FID. The rate constants for the other two processes were obtained from the product branching ratio plots shown in Figure 5; these data include experiments at lower pressure (without added SF 6 ) analyzed by GC-MS.…”

“…However, this community was unaware of the work of organic chemists who had observer the 1,2-interchange of bromine atoms on carbon scaffolds. [6] In 2001 the 1,2-dyotropic type 1 rearrangement of Cl and F atoms in CF 2 ClCF 2 CH 3 was reported by our laboratory. [7a,b] This isomerisation reaction frequently can be in competition with HX elimination.…”

Studying Double Group Transfer Reactions by Means of Computational Methods

“…Interestingly, the computed strongly negative Nuclear Independent Chemical Shifts (NICS) values which are exhibited by the transition states (in the range of -10 to -25 ppm) clearly show that these saddle points also fulfill the magnetic criterion of aromaticity [6,7]. NICS values were calculated inside the transient cyclic atomic array at the (3,+1) ring critical point of the electron density (as defined by Bader [16]) due to its high sensitivity to diamagnetic effects and its unambiguous character.…”

“…In these cases and according to the notation by M. T. Reetz, [5,6] the migration of the groups/atoms occurs through a static scaffold. Thus, those reactions where the migrating fragments interchange their relative positions are designated as Type I-dyotropic reactions while Type II-dyotropic processes involve transfers to new bonding sites without positional interchange (Scheme 4).…”

“…These transformations occur through the simultaneous migration of two atoms/groups from one compound to another in a concerted reaction pathway. This definition includes text-book reactions like the diimide reduction of double or triple bonds [3], (Scheme 1a) the uncatalyzed Meerwein-Ponndorf-Verley reduction (MPV) of carbonyl groups [4], (Scheme 1b) and some type II-dyotropic reactions which are characterized by the intramolecular transfer of the two groups (generally hydrogen atoms) [5,6] (Scheme 1c). The present report shall briefly review recent computational studies done on DGT reactions which have shown that these processes fulfill indeed the general features of typical pericyclic reactions.…”