I think that's possible, but I would strangle anyone who actually did that. At that point, not only are you pointlessly redefining the language just so it can feel slightly more familiar to people who are more comfortable with Python and the like, but you also completely lose the ability to enclose variables in the square brackets to make a closure.
If you're going to write C++, then write C++. Don't redefine language constructs to fit the patterns of your other favourite language.
I think you can
#define begin {
#define end }
#define lambda []
?