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. Author manuscript; available in PMC: 2020 Mar 13.
Published in final edited form as: J Am Chem Soc. 2019 Feb 27;141(10):4199–4203. doi: 10.1021/jacs.8b13757

Table 2.

Evaluation of Reaction Parameters a,b

graphic file with name nihms-1030605-t0005.jpg
entry Lewis acid (mol%) Brønsted base (mol%) Znl2/L8 (mol%) yield of 2a (%) er
1 B(C6F5)3 (10) NET3 (20) 10 >95 97:3
2 B(C6F5)3 (10) DBU (20) 10 0 ND
3 B(C6F5)3 (10) PMP (20) 10 >95 97:3
4 B(C6F5)3 (7.5) PMP (15) 7.5 90 97:3
5c B(C6F5)3 (7.5) PMP (15) 7.5 >95 97:3
6c B(C6F5)3 (5.0) PMP (10) 5.0 92 97:3
7 B(C6F5)3 (5.0 none 5.0 0 ND
8 none PMP (10) 5.0 0 ND
9 B(C6F5)3 (5.0) PMP (10) 0 0 ND
10 BF3·OEt2 (5.0) PMP (10) 5.0 0 ND
11 BPh3 (5.0) PMP (10) 5.0 0 ND
a

Conditions: 1-phenylnon-5-yn-1-one (1a, 0.2 mmol), organoborane, Brønsted base, ZnI2/L8 complex, CH2Cl2 (1.0 mL), under N2, 22 °C, 12 h.

b

Yield was determined by 1H NMR analysis of unpurified reaction mixtures with mesitylene as the internal standard. The er values were determined by HPLC analysis of the purified product.

c

The reaction mixture was allowed to stir at 40 °C.