Front or back?
I've read about a few conversions of 337s that had a single turbine conversion.
I think one had a garret in the front, which makes sense to make rear cargo loading easier, while another had a p&w in the back.
The turbine conversion would seem to kill a number if birds (more power, only one engine to maintain, possibly less chance of coolly the rear donk)
I note that the conversions were just one off, so possibly not a roaring commercial success...but I do remember seeing a very modern US prototype with a big pusher-could be a new take?
What would be the rationale for a single rear turbine?