Nonchair conformations in phosphorus-containing cyclohexanes. Crystal and molecular structures of cis- and trans-2-phenyl-2-oxo-5-tert-butyl-1,3,2-dithiaphosphorinanes and cis-2-phenyl-5-tert-butyl-1,3,2-dithiaphosphorinane

Stereoelectronic effects in biomolecules

“…Our laboratory and others have also provided additional support for these unusual conformational preferences in solution. [36][37][38][39][40][41] The conformational and configurational analysis36-38,42-54 of phosphorinanes (e.g., [11][12][13][14] has been based upon 31P chemical shifts, 38,45 Ar: 11, MeOPh-, 12, Ph; 13, ^-N02Ph; 14, 2.4-(N02)2Ph 3JHcop coupling constants, 35,55,56 and P=0 stretching frequencies. [51][52][53][54]57 Again all of the trans isomers are in a chair conformation with an axial ester bond.…”