Relations between RSA and Generalized Diffie-Hellman (GDH), factoring and GDH
Breaking the Generalized Diffie-Hellman (GDH) assumption is known to imply Factoring for Blum-integers. This is a result by Biham et al.
Since the (non)-equivalence of the RSA and Factoring assumptions is one of the biggest open questions in the RSA literature, it would be really surprising if there was a reduction from GDH to the RSA assumption, because then we would have the equivalence of the RSA and Factoring assumptions for Blum-integers given the result of Biham et al.