A joint experimental, in silico and NMR studies towards the rational design of iminium-based organocatalyst derived from renewable sources

GEROSA, G. G. ; SPANEVELLO, R. A.; SUAREZ, A. G. ; SAROTTI, A. M.

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 2015 p. 7626 - 7634

0022-3263

An efficient organocatalyst for iminium-ionbased asymmetric Diels−Alder (DA) reactions has beenrationally designed. The most influential structure−activityrelationships were determined experimentally, while DFT calculations and NMR studies provided further mechanistic insight. This knowledge guided an in silico screening of 62 different catalysts using an ONIOM(B3LYP/6-31G*:AM1) transition-state modeling, which showed good  correlation between theory and experiment. The top-scored compound was easily synthesized from levoglucosenone, a biomass-derived chiral enone, and evaluated in the DA reaction between (E)-cinnamaldehyde and cyclopentadiene. In line with the computational finding, excellent results (up to 97% ee) were obtained. In addition, the catalyst could be easily recovered and reused with no loss in its catalytic activity.