Some dictionaries say "much as" means "although." If so, is the following correct?
Much as I finished the work, the boss was angry with me.
Much as can nearly mean although, but not quite. An example would be "Much as I need the money, I am not going to take it." This could be rendered "Although I need the money a lot, I am not going to take it." Using much as emphasises the strength of the need.
"Much as I tried the boss was angry" works, but "Much as I finished the boss was angry" doesn't work. Perhaps it is because trying is on a scale and finishing is not.
"Much as" doesn't mean "although" exactly. In some cases, it can be replaced with "although", but not always.
"Much as" means "despite the extent to which" or "no matter how much", e.g.
Much as I loved him, I could not save him.
So, you can't say "Much as I finished the work, the boss was angry with me".