Chiral Diols. A New Class of Additives for Direct Aldol Reaction

Entry numbers in Table 3 did not appear in numerical order. ... (%)d ee. (%)e. 1. 4-ClC6H4. (S)-1. 10:3:0.1. 4a. R. 94. 79. 83. 2 no. 10:3:0. R. 82. 7...
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Vol. 72, 2007 Yan Zhou and Zixing Shan*. Chiral Diols. A New Class of Additives for Direct Aldol Reaction Catalyzed by L-Proline.

Page 9512. Entry numbers in Table 3 did not appear in numerical order. The corrected table is presented with an additional scheme to obtain 4. TABLE 3. Direct Aldol Reaction Assisted by (S)-BINOLa

entry 1 2 3 4 5 6 7 8 9 10 11 12 13 14

R 4-ClC6H4 4-BrC6H4 3-BrC6H4 2,6-Cl2C6H3 Ph 9-anthranyl i-Pr

additive

sub./cat./additive

product

configurationb

conversion (%)c

yield (%)d

ee (%)e

(S)-1 no (S)-1 no (S)-1 no (S)-1 no (S)-1 no (S)-1 no (S)-1 no

10:3:0.1 10:3:0 10:3:0.1 10:3:0 10:3:0.1 10:3:0 10:3:0.1 10:3:0 10:3:0.1 10:3:0 10:3:0.1 10:3:0 10:3:0.1 10:3:0

4a

R R R R R R R R R R Rf Rf R R

94 82 90 88 89 92 95 94 79 60 30 14 -

79 76 76 82 86 89 90 80 56 43 23 10 46 43

83 75 97 75 95 75 96 89 98 72 87 92 90 88

4b 4c 4d 4e 4f 4g

a The reaction was carried out in acetone/DMSO (3:1) at 0 °C for 48 h. b Assigned by comparison of the HPLC retention time of the product with reported data (ref 17b). c Based on the aldehyde recovery after column chromatography. d Isolated yield after column chromatography. e Determined by HPLC. f Assigned by analogy.

JO063319W 10.1021/jo063319w Published on Web 12/19/2006

686

J. Org. Chem. 2007, 72, 686