Nope. MTB rims are 559mm in diameter, 700C wheels are 622mm diameter.
Narrow(er) and slick(er) 26" tires are available, and help a lot with rolling resistance. I used the
Kenda/Sunlite City Slick 26x1.5" for a while, and Panaracer makes 26" Paselas in 1.25", 1.5", and 1.75" widths.