Disappointingly, I couldn't get any prominent professors of organic chemistry. Sanford, Jacobsen, Bertozzi and Breslow were all busts. (Maybe they were one of the people who didn't have to sign in, yeah, that's the ticket!) Daniel Nocera is a no-go, too. (See update below.)
Among pharma types, (your friend and mine!) Jeff Kindler has been to the White House many, many times. He first arrived on March 5, 2009 and visited 12 more times until his last visit on June 17, 2011. But Kindler has been active in politics for a while, I believe. (What was he doing at the White House after he was let go from Pfizer in December 2010? Who knows?) John Lechleiter, the CEO of Lilly has been to 1600 Pennsylvania Avenue a few times himself, although not nearly as many as Kindler. Lechleiter seems to hold the title for most prominent holder of a Ph.D. in chemistry (and most prominent process chemist!) to be invited to the White House. Merck CEO Ken Frazier, by contrast, seems to have been at the White House only once.
American Chemical Society CEO Madeleine Jacobs has been to the White House 8 times, with 3 of them being meetings with their relevant policy professionals. White House staffer Victoria Espinel (the "copyright czar") seems to show up in these logs on a regular basis. Once, she was in the room at the same time as Robert Massie, the president of CAS. For fans of C&EN, I'm disappointed to note that Rudy Baum hasn't appeared to have been to the White House.
Finally, our #chemjobs fibber Andrew Liveris (and his wife Paula) seem to be frequent visitors to the occupants of the White House with 19 visits. (See update 2) It gives me cold comfort that the two people in my little database search to have been at the White House are 1) the person who's laid off many, many chemists in his time and 2) the person who keeps telling the mainstream media how the country has a desperate shortage of chemical professionals.
Readers, try your hand out at the database and tell us in the comments who's been to the White House (use the "advanced search" feature.)
UPDATE: Lisa Jarvis of C&EN notes that Harvard's George Whitesides spends a lot of time (more than Liveris or Kindler!) at the White House.
UPDATE 2: An astute reader points out that Andrew Liveris is co-chair of the President's Advanced Manufacturing policy committee, and would be expected to visit the White House frequently.
*[I should take a moment and say that, within reason, there should be high levels of transparency for the behavior of elected officials. I don't really see this as a Democratic/Republican issue; I see this as a "those who have influence" versus "those who do not" issue.]