Any sale or encumbrance to the personal representative, his spouse, agent or attorney, or any corporation or trust in which he has a substantial beneficial interest, or any transaction which is affected by a substantial conflict of interest on the part of the personal representative, is voidable by any person interested in the estate except one who has consented after fair disclosure unless:

1. (1) the will or a contract entered into by the decedent expressly authorized the transaction; or

2. (2) the transaction is approved by the court after notice to interested persons.

   UNDER FORMER PROVISIONS GOVERNING PURCHASES BY EXECUTOR OR ADMINISTRATOR