"sent" mail box, how the heck do you transfer to mac

Hi, I'm trying to switch iphones and back up old stuff, and am realizing I want to BU all my "sent" mail from the iphone. I am at a total loss, I can sync with mail program but don't see how to bring "sent mail box" on Iphone to mac. The notes seem to synch from IP to Mac but can't figure out how to get "sent" mail. When I search forums and net, I can't find an answer, mainly "can't send mail" problems. So if anyone can give me a hand that would be great, thanks.