Show how the following conversion can be carried out using suitable reagents.

Conversion of an imine to an enamine using CH3MgBr in ether and H3O+.

Conversion of an imine to an enamine using H2 and Ni catalyst.

Conversion of an imine to an enamine using CH3CH2MgBr in ether and H3O+.

Conversion of an imine to an enamine using H2O, H+, OH-, and heat.