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. Author manuscript; available in PMC: 2012 Feb 15.
Published in final edited form as: Synthesis (Stuttg). 2008 Apr;2008(8):1306–1315. doi: 10.1055/s-2008-1072516

Table 4.

Asymmetric Protonation of Homoenolate Equivalentsa

graphic file with name nihms248680t25.jpg
Entry Azolium salt Yieldb (%) of 22 + 23 ee (%) of 22
1 15 51 33
2 16 –c 9d
3 17 –c 23d
4 18 58 55
5 19 45 59
6 20   0 –
7 21   0 –
a

Reaction conditions: 15–21 (0.02 mmol), DIPEA (0.05 mmol), 14 (0.20 mmol), EtOH (0.41 mmol), THF (1.0 mL), r.t., 12–24 h.

b

Isolated yields.

c

Not isolated.

d

Assessed by HPLC of crude reaction mixture.