Trialkylphosphine ring opening

Lewis Acid Assisted Trialkylphosphine Ring Opening... 

Although NHCs have to be considered as even more electron-donating than trialkylphosphines, the catalytic performance of 53 turned out to be just comparable to 52, but not significantly better. It depends on the substrate whether the one or the other catalyst performs slightly better in ring opening metathesis polymerization (ROMP). 

The photochemical desulfurization of 4-amino-l,3 tWazolium salts 224 or mesoionic 2,3,5-triaryl-l,3-thiazolium-4-olates 228 in the presence of trialkylphosphite or trialkylphosphine, affording ring-opened cinnamic acid derivatives 226 [88JCS(P1)189] and 230 (83JHC245) or quinolinones 231 [88JCS(PI)189] is assumed to proceed via intermediate azetine derivatives 225 and 229, respectively (Scheme 62). 

With enmie 64 in hand, we initially observed that trialkylphosphines alone could not affect ring-opening in these less strained systems. As seen in Table 2, a series of trialkylphosphine reagents were explored, all returning starting material (entries 1 and 5). As seen earlier, prolraiged reaction times... 

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