Sullivan & Cromwell has appointed partner Joseph Shenker vice chairman, making him the likely successor to the firm’s chairman, H. Rodgin Cohen, who is expected to step down when he turns 65 in 2009.

Shenker, 49, is head of the firm’s real estate practice and regarded as a pioneer in the field of real estate securitization. He also serves on the firm’s management committee, where he has overseen the firm’s financial and administrative affairs.