Looking to put a man cave and shop in my detached building. 150 feet away from my service. I want to run 50 amp 220 in 6 gauge copper line would this allow me to run a window ac, a beer fridge, exhaust fan and some power tools with a pretty aggressive power usage. Would this work?

Using your numbers, voltage drop is 2.47%, within design parameters of 3%. You will be using a sub panel?

Since you won't be operating all of the tools at once, you should be fine. You didn't say the size of your shop, so it's hard to guess how large of an air conditioner you will need. Consider running the larger tools, and the AC with 240 if you can. This will help with startup of the motors and compressors. You will need a 4 wire feed to the sub-panel and adequate grounding rod(s) as well Since you have to trench, are you planning to bury conduit and pull wire? If so, you can add conduit for telephone, intercom or cable TV. (You did say man cave). Are you doing anything for heat?