Acetonyltriphenylphosphonium Bromide and Its Polymer-Supported Analogues as Catalysts for the Protection of Carbonyl Compounds as Acetals or Thioacetals.

Both acetonyltriphenylphosphonium bromide (ATPB) and poly-p-styryldiphenylacetonylphosphonium bromide (PATPB) are excellent catalysts in the protection of aldehydes as acetals or thioacetals. In general, ATPB is highly selective as ketones do not give good yields of ketals with this catalyst. [ABSTRACT FROM AUTHOR]