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. 2012 Sep 3;8:1443–1451. doi: 10.3762/bjoc.8.164

Table 1.

Evaluation of the sulfonimidoyl-containing thiourea organocatalysts in the asymmetric Biginelli reaction to afford scalemic dihydropyrimidinone (S)-20.

graphic file with name Beilstein_J_Org_Chem-08-1443-i001.jpg
entry chiral
thiourea		 catalyst loading (mol %)/
concentration (mol/L)		 time (d) substrate concentration (mol/L)a yield (%) er (%)b
1 (S)-3 10/0.025 3 0.25 28 50:50
2 (SS,SC)-18 10/0.025 3 0.25 32 50:50
3 (RS,SC)-19 10/0.025 3 0.25 30 50:50
4 (S)-12 10/0.025 3 0.25 42 58:42
5 (S)-13 10/0.025 3 0.25 21 57:43
6 (S)-12 10/0.025 5 0.25 89 58:42
7 (S)-13 10/0.025 5 0.25 40 57:43
8 (S)-12 20/0.05 5 0.25 90 59:41
9 (S)-13 20/0.05 5 0.25 42 57:43
10 (S)-12 10/0.0025 5 0.025 92 72:28
11 (S)-12 1/0.0025 5 0.25 53 51:49

aWith respect to urea. bDetermined by HPLC analysis with a chiral stationary phase.