What a ridiculous assertion!
Ronald Reagan had 4 appointments to the Supreme Court during his two terms as President. In 1981, he replaced Justice Stewart with Sandra Day O'Connor. In 1986, he elevated Justice Rehnquist to Chief Justice to replace Chief Justice Burger and appointed Antonin Scalia to the Court to take the seat vacated by Justice Rehnquist. And in 1987, he appointed Anthony Kennedy to the Court (after losing battles to appoint Robert Bork and Douglas Ginsburg).
As for the assertion that Reagan's appointees "are now considered left leaning," it's beyond absurd to claim that anyone thinks (or ever thought) of William Rehnquist or Antonin Scalia as "left-leaning" except, perhaps, when a car either was riding in made a sharp left turn. Indeed, Rehnquist and Scalia are both considered judicial pointmen in the "conservative revolution."
Justice Kennedy might have once been considered to be a slightly leftward-leaning moderate, but more recent terms have shown him to be consistently voting with the established conservatives on the Court. In the last term (October Term, 2007), in non-unanimous cases, Kennedy sided with Roberts 83% of the time, sided with Scalia 75% of the time, and sided with Alito 80% of the time. In the term before that (OT 2006), in the same kinds of cases, Kennedy sided with Roberts 81% of the time, with Scalia 72% of the time, and with Alito 87% of time. Whatever claims of leftism might have once followed Kennedy around are now long since abandoned.
Justice O'Connor might have, on certain issues, been considered somewhat leftward-leaning, but her overall voting record suggests that either: (1) she was much more conservative than most think; or (2) the Justices who are considered to be conservatives must actually be liberals. In the 9 terms between OT '95 and OT '04, O'Connor voted most frequently with Rehnquist, Scalia, Kennedy, and Thomas; at the lowest, she voted with Rehnquist 79% of the time (OT '01), with Scalia 81% of the time (OT '04), with Kennedy 83% of the time (OT '95) and with Thomas 81% of the time (OT '02). That's hardly a liberal voting record, I would say.