Boron doesn't really work, of course. I mean to say: it's electron-donating, sure, but you couldn't use it in medicinal chemistry, which is where Derek wants to use it. You can't put boron compounds in water -- well, you can, but they stop being boron compounds because they react swiftly and completely with water.

It's an interesting thought-experiment though. To me, it points out the supreme un-utility of theoretical chemistry, which is the field I left to become a computer programmer. But maybe I'm just bitter.

I came up with some other weird ideas. One was to use tritium instead of a proton. Tritium decays to ³He by emitting a beta particle; the process has a half-life of 12.43 years. The new helium atom would fall off (it's a leaving group!), taking two electrons and leaving behind a radical carbon. In this case the radioactivity of the tritium would be incidental to the chemical change triggered after the decay. (As an aside, I don't know of any radioactive drug where the change in chemical properties after the decay is used. I may ask our neighbor, a doctor who does nuclear medicine over at the U of A.)

Another weird idea would be to stick on some meson or other particle. Something with two or three +2/3 quarks, for a net charge of +4/3 or +2. On sober reflection, this would of course tend to draw electrons away from the substituted carbon, so I don't know what I was thinking.