I just know of this addon here: https://developer.blender.org/diffusion/BAC/browse/master/materials_cycles_converter.py
The bad news is, it is gone and deleted. Not longer available. And it was just a one way road. From BI to Cycles. Your best bet is to start with the material system and renderer that you want to use for the final result.
Sorry that i have no better news.
Kind regards
Reiner