Understanding the regio- and chemoselective polar [3+2] cycloaddition of the Padwa carbonyl ylides with α-methylene ketones. A DFT study

The regio- and chemoselective polar [3+2] cycloaddition (32CA) of the Padwa carbonyl ylide (CY) with α-methylene ketone (αMK) to yield the oxa-bridged spirocycloadduct has been studied using the DFT method at the B3LYP/6-31G(d) computational level. Six reactive channels associated to the stereo-, regio-, and chemoselective approach modes of the CY to the CC and CO reactive sites of the αMK have been analyzed. DFT calculations for this cycloaddition are in complete agreement with the experimental outcome, explaining the reactivity and selectivity of the formation of the [3+2] cycloadduct. Analysis of the global and local electrophilicity and nucleophilicity indices allows an explanation abou…

Understanding the Influence of the Trifluoromethyl Group on the Selectivities of the [3+2] Cycloadditions of Thiocarbonyl S ‐methanides with α,β‐Unsaturated Ketones. A MEDT study

Understanding the kinetic solvent effects on the 1,3-dipolar cycloaddition of benzonitrile N-oxide: a DFT study

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, ISSN : 0894-3230, DOI : 10.1002/poc.1858, Issue : 7, Volume : 24, pp. 611 – 618, JUILLET 2011.

Understanding the role of the Lewis acid catalyst on the 1,3-dipolar cycloaddition of N-benzylideneaniline N-oxide with acrolein: a DFT study

Abstract The Lewis acid (LA) catalyzed 1,3-dipolar cycloaddition of N -benzylideneaniline N -oxide with acrolein has been studied using DFT calculations. Coordination of AlCl 3 to the acrolein oxygen atom produces a drastic change in the mechanism along the more favorable meta reactive channel. The process is characterized by a strong nucleophile/electrophile interaction allowing the formation of a zwitterionic intermediate, a Michael-type addition. The subsequent ring closure constitutes the rate-determining step. The energies obtained with the inclusion of solvent effect by means of the polarizable continuum model are in good agreement with experimental findings. Analysis of the global an…

Theoretical study of the regio- and stereoselectivity of the intramolecular Povarov reactions yielding 5H-chromeno[2,3-c] acridine derivatives

The intramolecular Povarov (IMP) reactions involved in the synthesis of 5H-chromeno[2,3-c] acridine derivatives [Tetrahedron Lett., 2010, 51, 3071–3074] have been studied using density functional theory (DFT) methods. The studied IMP reaction is a domino process that comprises two consecutive reactions: (i) a BF3 Lewis acid catalysed intramolecular aza-Diels–Alder (IMADA) reaction of an alkene tethered chromene imine (ATCI) giving a formal [4 + 2] cycloadduct, and (ii) a 1,3-hydrogen shift yielding the final chromeno product. The possible regio-(fused/bridged) and stereo-(cis/trans) isomeric channels associated with the IMADA reaction were thoroughly investigated and analysed. The activatio…