Conformation of alkenes

The orbital phase theory was applied to the conformations of alkenes (a- and P-substituted enamines and vinyl ethers) [31] and alkynes [32], The conformational stabilities of acetylenic molecules are described here. 

This interaction is an example of 1,3-allylic strain ° This type of steric strain arises in eclipsed conformations when substituents on the double bond and the C(3) group, which are coplanar, are large enough to create a nonbonded repulsion. The conformation of alkenes is an important facet with regard to the stereoselectivity of addition... 

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