E-2-Benzylidenebenzocycloalkanones. IV. Studies on transmission of substituent effects on 13C NMR chemical shifts of E-2-(X-benzylidene)-1-tetralones, and -benzosuberones. Comparison with the 13C NMR data of chalcones and E-2-(X-benzylidene)-1-indanones

摘要: Abstract Single substituent parameter (SSP) and dual (DSP) analyses were applied to study the transmission of effects on selected 13 C NMR chemical shifts cyclic chalcone analogues, E -2-(4′-X-benzylidene)-1-tetralones ( 2 ) -2-(4′-X-benzylidene)-1-benzosuberones 3 ). In order how geometry analogues affects similar investigations with respective chalcones 4 also performed. The results obtained earlier five-membered analogue -2-(4′-X-benzylidene)-1-indanones 1 involved in comparisons. Geometry optimization unsubstituted 1a , 2a 3a 4a as well substituted was performed by ab initio quantum calculations. Both SSP DSP reflected that resonance contribute more shift C-α (C2), while inductive primarily affect C-β (C10) enone moiety all four series. This latter effect, however, is far not pronounced former one. It found analysis data ρ F R values) δ C2 can serve a measure choice conformation (planarity) investigated enones