Bifunctional squaramides with benzyl-like fragments: analysis of CH⋯π interactions by a multivariate linear regression model and quantum chemical topology

Abstract

We analyzed 15 bifunctional squaramides with benzyl-like fragments in a Michael addition. These substituents are susceptible to form CH⋯π interactions and have distinct properties: electronic features, stereogenic center, as well...

Harvesting the fragment-based nature of bifunctional organocatalysts to enhance their activity

“…[28][29][30][31][32][33][34][35] Alternative approaches aim at identifying exactly which NCI motifs between the catalyst and the substrate drive the selectivity and probe their individual contribution to the reaction outcome. [36][37][38] To this end, the energy difference between stereocontrolling transition states has been correlated with interaction energies associated with the relevant chemical motifs or distances using truncated structures [39][40][41][42][43][44] or decomposition schemes. 45,46 Despite the success of these fragment-based methods, the modular nature of multifunctional organocatalysts is not fully taken into account and the approach is not applicable to cover properties that also rely on the influence of covalent bonding.…”

The Chameleonic Nature of the Nitro Group Applied to a Base-Promoted Cascade Reaction To Afford Indane-Fused Dihydrofurans

“…General Procedure B. In a screw cap vial containing a stirred mixture of 1a (50.0 mg, 0.20 mmol, 1.0 equiv) and the catalyst C-1 19 (2.2 mg, 3.0 mol %) in toluene (2.0 mL, 0.1 M) was added acetylacetone (41 μL, 0.40 mmol, 2.0 equiv). After 24 h the reaction mixture was concentrated under reduced pressure.…”

An update on chiral phosphoric acid organocatalyzed stereoselective reactions

“…Examples of organocatalysts that partially transfer a proton are thioureas, squaramides, and diols. [1][2][3][4][5][6] On the other hand, catalysts that completely transfer a proton to the substrate are Chiral Phosphoric Acids (CPAs), N-triflyl phosphoramides, chiral disulfonimides, and imidodiphosphate-type Brønsted acids. [7][8][9][10][11] Since the first report in 2004, chiral phosphoric acids have been establishing new trends with robust synthetic protocols and are undoubtedly the reference in Brønsted acid-type organocatalysis.…”

“…Examples of organocatalysts that partially transfer a proton are thioureas, squaramides, and diols. 1–6 On the other hand, catalysts that completely transfer a proton to the substrate are Chiral Phosphoric Acids (CPAs), N -triflyl phosphoramides, chiral disulfonimides, and imidodiphosphate-type Brønsted acids. 7–11…”