a. i. Unhindered keto group is converted to cyclic ketal and then followed by reduction with by reduction with Raney Ni.
ii. A ldehyde is more reactive than the keto group and is converted to cyclic thio acetal and the reduction is effected with Raney Ni.
b.
group together with other functional groups that react with strong base must be reduced by Clemmensen reduction, provided they are stable in acid. If they are sensitive to acid and stable in base W.K. method should be used . Raney Ni desulphurisation occurs under neutral conditions, but it cannot be used with reactions with good leaving groups (such as `I^(ɵ)`) because (-SH) group is an excellent nucleophilic group.
