wat r gauche conformers?????

these are basically the conformational isomers where 2 vicinal groups are seperated by torsion angle of 60 degrees ...

In stereometry, gauche interactions hinder bond rotation. For example, sighting along the C2-C3 bond in staggered butane, there are two possible relative potential energies. The two methyl groups can be in an anti-bonding relationship, or offset at sixty degree dihedral angles. In the latter configuration, the two methyls are said to be in a gauche relationship, and the relative potential energy of each methyl-methyl gauche interaction is 0.9 kilo-calories per mole (4 kJ/mol). In general a gauche rotamer is less stable than an anti-rotamer...

Let us take Butane....(C₄H₁₀)....

We can begin the conformational structures as....

Tht is the Eclipsed structure ....as methyl - methyl overlap there will b maximum repulsion....thus highest energy & this form will b the least stable...

Next v can rotate the back Carbon so tht methyl -methyl make an angle of 60⁰..This is the Gauche conformer...

Approved