The above reaction is an example of the stereoelectronic selectivity-based strain relief ( alleviation of 1, 3-diaxial interactions, torsional strain, etc . ).
12.
Both conformations are free of torsional strain, but, in the gauche conformation, the two methyl groups are in closer proximity than the sum of their van der Waals radii.
13.
Further work has shown that the effect of 1, 3-dioxanes and 1, 3-dioxolanes on disarming sugars can be attributed to the electronics of the systems as well as torsional strain.
14.
Then follows a torsional strain relieving rotation to the trans isomer ( not shown ) and step "'C "'is a beta-hydride elimination step with the formation of a new palladium-alkene ? complex ( "'5 "').
