is much reduced compared to QM level of theory. Furthermore, inversion of the
imaginary normal mode before reconstructing the full Hessian means that each TS is
represented as a minimum on the PES, making structure optimization less challenging than a conventional saddle point optimization. More recent developments of this
methodology have seen the workflow being automated such that reaction queries can
be submitted as 2D structures via a web interface, known as the CatVS program [51].
5 Quantitative Structure-Selectivity Relationships (QSSRs)
Quantitative structure-activity relationships (QSARs) have been used by biologists
and medicinal chemists for more than six decades [52]. During ligand screening,
more often than not, only a portion of the data collected offers insightful information,
R 1
N
H
OR 3
O
O
R 2
2
R 1
N
H
OR 3
O
O
R 2
PPh 2
PPh 2
R
R
P
P
R’
R’’
R’’
R’
Chiral ligands:
Chiral ligands
Rh catalyst, H
Fig. 11 Quantum-guided molecular mechanics (Q2MM) calculation of ee in rhodium-catalysed
hydrogenation using a transition state force field
170
R. Ardkhean et al.