You could transfer the points to Hawaiian Air, and then redeem the HA miles for Alaska Air Tickets, since they are a HA redemption partner. Check out WWW.HAWAIIANAIR.COM for more info.

If you really need the points in your Alaska acct, you could transfer the AMEX points to Marriott or Starwood, and then transfer them to Alaska - but you loose a lot of points in the conversion factors. I would go the HA route.