Allylic coupling transoid

In inter alia the t-butyl substituted compound 118, the cisoid allylic couplings constants to H, 2.3 Hz and that to H", 1.9 Hz together with the transoid counterparts to H, 2.6 Hz and to H", 2.4 Hz indicated a slight variation of the coupling constant with substituent electronegativity In 119 the cisoid and transoid coupling constants were 2.4 and 2.8 Hz... 

Figure 12.16. Dependence of allylic coupling constants on stereochemistry. Solid lines Transoid (Jbx) dashed lines Cisoid Ja - 0 is the... 

Figure 2.58. is cisoid-a y ic coupling while is transoid-allylic coupling. Torsional angle (j) is the angle which C—makes with the dashed line through the allylic carbon atom drawn parallel to the plane in which the n bonds lie. 

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