Harnessing the Lewis Acidity of HFIP through its Cooperation with a Calcium(II) Salt: Application to the Aza-Piancatelli Reaction.
A method to extend the scope of the aza-Piancatelli reaction between 2-furylcarbinols and anilines is depicted. We found that 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) is the solvent of choice for this transformation, as it outcompetes the usual solvents in terms of rate and yield. Side reactions and other issues raised by the title reaction are prevented, thereby providing an avenue to complex molecules that were previously inaccessible. Lewis acidity studies and computations were carried out to unveil the role of HFIP. Based on these results, we propose that HFIP is, in fact, acting as a Lewis acid and that its acidity can be enhanced when combined with a calcium(II) salt.
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France. david.leboeuf@u-psud.fr.
David
D
Lebœuf
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France.
Lucile
L
Marin
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France.
Bastien
B
Michelet
Sorbonne Universités, UPMC Univ. Paris 6, Institut Parisien de Chimie Moléculaire (IPCM), CNRS UMR 8232, 4, place Jussieu, 75005, Paris, France.
Alejandro
A
Perez-Luna
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France.
Régis
R
Guillot
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France.
Emmanuelle
E
Schulz
Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS UMR 8182, Université Paris-Sud, Université Paris-Saclay, Bâtiment 420, 91405, Orsay cedex, France. vincent.gandon@u-psud.fr.|Institut de Chimie des Substances Naturelles (ICSN), CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 1, av. de la Terrasse, 91198, Gif-sur-Yvette, France. vincent.gandon@u-psud.fr.
Vincent
http://orcid.org/0000-0003-1108-9410
V
Gandon
alcohol; calcium; cooperative catalysis; density functional calculations; electrocyclic reactions