Mr Shailesh as per sec 54f exemption is available from cap gain on sale of any long term capital assets on purchase of one residential house. provided you do not own any other house property.
and as per sec 54 exemption from long term capital gain is available on sale of a house property if another house is purchasedc within 2 years or construction is completed within three years.
now benifit of sec 54 is available to you not of sec 54f
and it is well cleared that exemption is restricted to only one house property not for more
and you dont need to transfer property to son moreover if he is minor the transfer will be of no consequnce and this property will be deemed to be yours
hope it helps you