Fig. 5: Mechanistic studies of the reactivity of the cycloisomerization.

a 1H NMR studies of a mixture of 1b and (R)-CPA. b 31P NMR studies of mixture of 1b and (R)-CPA.

a 1H NMR studies of a mixture of 1b and (R)-CPA. b 31P NMR studies of mixture of 1b and (R)-CPA.