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. Author manuscript; available in PMC: 2010 May 15.
Published in final edited form as: J Org Chem. 2009 May 15;74(10):3689. doi: 10.1021/jo802784w

TABLE 2.

DBU-Mediated Condensation Reactions of 3

graphic file with name nihms109915t2.jpg
entry RCHO conditions, rxn time (h) products 4–7: (%)E/Z ratio,a yieldb δ (ppm); mult, J (Hz)
1 graphic file with name nihms109915t3.jpg Method A, 4 4: 6/94;c 86% c E-isomer:−110. 5; d, 21.3
2 Method B, 17 4: 78/22; 93% Z-isomer: −120.5; d, 36.6
3 graphic file with name nihms109915t4.jpg Method A, 2.5 5: 3/97; 92% E-isomer:−104. 8; d, 21.3
4 Method B, 16 5: 67/33; 83% Z-isomer: −115.0; d, 33.6
5 graphic file with name nihms109915t5.jpg Method A, 4 6: 74/26; 78% E-isomer: −115.7; broad s
6 Method B, 17 6: 86/14; 81% Z-isomer: −119.7; d, 33.6
7 graphic file with name nihms109915t6.jpg Method A, 2.5 7: 54/46; 74% E-isomer: −117. 5; broad s
8 Method B, 16 7: 67/33; 69% Z-isomer: −125.7; d, 36.6
a

Relative ratio of diastereomers in the crude reaction mixture determined by 19F NMR prior to isolation. No change in olefin ratio was observed after purification.

b

Yields of isolated, purified products (reactions were performed under similar conditions using either Method A or Method B, but were not optimized for individual cases).

c

Practically no change in E/Z ratio and yield was observed upon increasing the sulfone from 1.2 to 1.4 molar equiv (compare entry 4, Table 1).