The reaction of a new cationic complex, [Cp-(CO) 2 Mo(η 4 -2-SPh-C 6 H 7 )] + PF 6 -(3), with carbon and sulfur nucleophiles was found to give in most cases the C-4 addition products 4 in good yield. The X-ray crystal structure of one of the addition products 4b confirms the regio-and stereochemistry of the reaction.

The reactions of a new cationic complex, [Cp(CO)2Mo(η4‐2‐methyl‐3‐SPh‐C4H4)]+ PF−6 (3), with carbon, hydride, and nitrogen nucleophiles were found to give only the C‐1 addition products in good yield. The X‐ray crystal structures of two of the addition products 4a and 4e confirm the regio‐ and stereochemistry of the nucleophilic additions.