sentence: Under optimized conditions low precursor amounts of 5 nmol ( cyclononyne ) and 50 nmol ( norbornene - β - Ala-Phe-OMe ) still allowed RCY of 56 % and 47 % , respectively.In a very recent report , Zlatopolskiy and coworkers applied their F-labeled nitrone , C - ( 4 - [ F ] fluorophenyl ) - N-phenyl nitrone , for the first formation of F-labeled β - lactames via the CuI-catalyzed Kinugasa reaction [ 21 ] ( Table 3 ) .