Explaining the Disparate Stereoselectivities of N-Oxide Catalyzed Allylations and Propargylations of Aldehydes

Abstract

A simple electrostatic model explains the enhanced stereoselectivity of N-oxide catalyzed allylations compared to propargylations, which in turn explicates the dearth of stereoselective N-oxide propargylation catalysts. These results suggest that N-oxide catalysts that are effective for both allylations and propargylations can be designed by targeting inherently stereoselective ligand configurations and through the manipulation of distortion effects in the operative transition states.

autoDIAS: a python tool for an automated distortion/interaction activation strain analysis

“…This analysis can be applied to single geometries or multiple geometries along a scan or reaction coordinate, to provide information on the nature of interaction between the fragments and the potential energy surface. This method has been widely applied for a broad range of chemical systems such as cycloadditions, ene reactions, metal complexes and catalysis, organocatalysis, and addition and substitution reactions …”

“…This analysis can be applied to single geometries or multiple geometries along a scan or reaction coordinate, to provide information on the nature of interaction between the fragments and the potential energy surface. This method has been widely applied for a broad range of chemical systems such as cycloadditions, [6][7][8][9][10][11][12][13][14][15][16][17][18] ene reactions, [19] metal complexes and catalysis, [20][21][22][23][24][25][26][27] organocatalysis, [28][29][30][31] and addition [32] and substitution reactions. [33][34][35] The implementation of a DIAS analysis is straight forward and can be performed using any electronic structure software.…”

Characterization of Highly Coordinated Allylgermanes: Pivotal Players for Enhanced Nucleophilicity and Stereoselectivity

“…Subsequently, the exchange of a chloride of 10 with a perchlorate by AgClO 4 , followed by the addition of 1,10‐phenanthroline afforded the cationic 6‐coordinated allylgermane 11 (Scheme B, Figure B). Notably, cationic 6‐coordinated allylmetals have been proposed as possible structures in the transition state of allylsilanes by Denmark, Malkov, and Wheeler . Our structural determination of 11 is the first experimental evidence that characterizes the cationic and highly coordinated state in the group 14 allylmetals.…”

Reaction-based machine learning representations for predicting the enantioselectivity of organocatalysts

“…S1 †). [84][85][86] Since each of these can lead to thermodynamically accessible reaction pathways, and the stereoselectivity is largely a consequence of which ligand arrangement is low-lying for a particular catalyst, all diastereomeric TSs were considered viable and the e.e. calculated from a Boltzmann weighting of the relative energy barriers.…”