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. 2020 Jul 3;85(15):10022–10034. doi: 10.1021/acs.joc.0c01282

Table 1. Optimization Study of the Cyclocarbonylative Sonogashira Reaction Between 2-Ethynylbenzamide 1 and Iodobenzene 2a.

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          selectivityc (%)
entrya solvent T (°C) t (h) conversionb (%) 3a 4a 5a
1 CH2Cl2 100 4 80 57 (34) 43 (21)  
2 CH2Cl2 100 8 78 39 61  
3d CH2Cl2 100 4 69 28 72  
4 CH2Cl2 70 24 79 29 71  
5 CH2Cl2 50 24 78 21   79 (42)
6 THF 100 4 94 29   71 (44)
7 THF 50 24 79 21   79
8 THF 30 24 16 26   74
9 CH3CN 100 4 85 78   22
10 CH3CN 50 24 83 38   62
11 DMF 100 4 100 33 32 35
a

All reactions were carried with 2-ethynylbenzamide 1 (1.0 mmol), iodobenzene 2a (1.0 mmol), CO (20 atm), PdCl2(PPh3)2 (0.4 mol %), Et3N (1.5 mL), and the solvent (4.0 mL), unless otherwise stated.

b

Conversion was determined by the 1H NMR peak integration on the crude product.

c

Selectivity was estimated by 1H NMR spectroscopy; isolated yields of pure products are reported in parentheses.

d

Reaction performed with 1 mol % of PdCl2(PPh3)2.