Triarylallenyl cations

The formation of solvent-incorporated products 8 suggested that triarylallenyl cations 7 are formed by photolysis of the corresponding chloroallenes 6 (equation 2). However, the products 8 obtained by photolysis were attributed to attack by nucleophiles at /-positions of the allenyl cation. Although allenyl cations are ambident cations and can produce allenyl or propargyl derivatives by attack at the a- or /-position, respectively, only /-attack was observed in this photolysis of triarylchloroallenes. This result is parallel to that observed by Schiavelli and coworkers9 in the solvolysis of these systems (vide infra) which therefore supports the formation of allenyl cations in the photolysis. 

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