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. 2018 Jan 29;8(3):2166–2172. doi: 10.1021/acscatal.7b04395

Table 1. Rh-Catalyzed o-C–H Alkynylation of Ethyl Benzoate and Benzyl Methyl Ether: Optimization Conditions24.

graphic file with name cs-2017-04395t_0012.jpg

entry DG variation from the “standard conditions”a yield (%)b
1 ester none 58–69
2 ester at 25 °Cc 35
3 ester at 65 °Cc 16
4 ester with Ag2CO3 (0.5 equiv)d 41
5 ester with K2CO3 (1 equiv)d 5
6 ester in dichloromethanee 8–14
7 ester in toluenee 0
8 ester in t-AmOHe 0
9 ester in Et2Oe 4
10 ester in EtOAce 18
11 ester in MeOHe 0
12 ether none 0
13 ether at 100 °Cc 50–64
14 ether without [Cp*RhCl2]2 0
15 ether without Ag2CO3 0
16 ether without LiOAc 0
17 ether without AgSbF6 0
18 ether with AgOAc (1.2 equiv)f <1.5
19 ether AgOAc (1 equiv) + Ag2CO3 (0.2 equiv)g 12
20 ether in toluenee 0
21 ether in tert-amOHe 0
22 ether in 1,4-dioxanee 0
23 ether with TIPS-acetyleneh 0
24 ether with [Cp*IrCl2]2i 0
25 ether with Pd(OAc)2i 0
26 ether with [RuCl2(p-cymene)]2i <3
a

Standard reaction conditions: 2a or 4a (0.2 mmol), 1 (2 equiv), [Cp*RhCl2]2 (2.5 mol % for DG = ester, 3 mol % for DG = ether), Ag2CO3 (1 equiv), AgSbF6 (0.2 equiv), LiOAc (0.2 equiv), DCE, 16 h, 45 °C.

b

Yield of the monoalkynylated product determined by 1H NMR using bromomesitylene as internal standard.

c

Instead of 45 °C.

d

Instead of Ag2CO3 (1 equiv).

e

Instead of DCE.

f

Instead of Ag2CO3 and LiOAc.

g

Without LiOAc.

h

Instead of 1.

i

Instead of [Cp*RhCl2]2.