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. Author manuscript; available in PMC: 2017 Feb 18.
Published in final edited form as: Angew Chem Int Ed Engl. 2016 Jan 25;55(8):2929–2933. doi: 10.1002/anie.201510910

Table 1.

Optimization of the zinc triflate catalyzed asymmetric ynamide addition to trifluoroacetophenone.

graphic file with name nihms768905t1.jpg
entry ligand R conditions yield (%) ee (%)
1 L1 n-Bu DCE, 25 °C, 20 h 75 48
2 L2 n-Bu DCE, 25 °C, 20 h 95 44
3 L3 n-Bu DCE, 25 °C, 20 h 89 33
4 L4 n-Bu DCE, 25 °C, 16 h 27 3
5 L5 n-Bu DCE, 25 °C, 20 h 15 22
6 L6 n-Bu DCE, 25 °C, 16 h 25 14
7 L7 n-Bu DCE, 25 °C, 16 h 72 45
8 L8 n-Bu DCE, 25 °C, 16 h 87 89
9 L9 n-Bu DCE, 25 °C, 20 h 15 0
10 L10 n-Bu DCE, 25 °C, 16 h 93 80
11 L11 n-Bu DCE, 25 °C, 16 h 22 9
12 L8 allyl DCE, 25 °C, 16 h 88 86
13 L8 n-Bu CH2Cl2, 25 °C, 20 h 95 87
14 L8 n-Bu CHCl3, 25 °C, 20 h 95 86
15 L8 n-Bu toluene, 25 °C, 16 h 70 78
16 L8 n-Bu THF, 25 °C, 16 h 55 66
17 L8 n-Bu ACN, 25 °C, 20 h 90 31
18 L8 n-Bu EtOH, 25 °C, 20 h 5 n.d.
19 L8 n-Bu DCE, 0 °C, 45 h 78 93
20 L8 n-Bu DCE, −10 °C, 51 h 73 91
21a L8 n-Bu DCE, −20 °C, 24 h 96 96

DCE=1,2-dichloroethane.

a

(EtO)3PO (20 mol%).