Tetrahedron p. 3523 - 3534 (1989)
Update date:2022-09-26
Topics:
Ideses, Rut
Shani, Arnon
For construction, by the Wittig reaction, of conjugated dienes with specific stereochemistry (either Z or E) at the newly formed double bond, without isomerization of the existing ("old") double bond, it is better to react a reactive (nonstabilized) saturated ylide with an α,β-unsaturated aldehyde.The opposite approach, namely, the reaction of a moderate (semi-stabilized) allylic ylide with a saturated aldehyde produces a mixture of geometric isomers, as a result of increased production of the E-configuration at the new double bond, and significant isomerization of the existing double bond.The proposed betaine structure for the intermediate could account only for the two equivalents of Li reaction.In other reactions, the less stable erythro-oxaphosphetane is probably the intermediate, produced by an early anti- or gauche C-C bond formation from the ylide and the carbonyl, from which the Z-double bond is then formed.
View MoreValiant Fine Chemicals Co., Ltd.
Contact:+86 535 6101878/6374484
Address:11 Wuzhishan Rd.,YTETDZ,Yantai,264006,Shandong,China
Hubei Onward Bio-Development Co., Ltd.
Contact:+86-718-8417012
Address:No.517,Shizhou Avenue,Enshi City,Hubei Province,China,445002
Nanjing chemipioneer pharmaceutical & technology Co., LTD
website:http://www.chemipioneer.com.cn
Contact:+86-25-52685700
Address:Room 305,A Block,Biological-Medicine Building,Business Start-up Center,Xin-ke 1st Road, High-tech development zone,Nanjing city,Jiangsu Province, China
Shanghai Balmxy Pharmaceutical Co., Ltd
Contact:0086-21-24206007
Address:Room 402, 15#, No. 909 wangyue Road, shanghai, P. R. China
Hangzhou Hysen Pharma co.,Ltd.
website:http://www.hysenpharma.cn/
Contact:0086-571-88298791
Address:#701,Gudun Road Hangzhou
Doi:10.1021/jo01298a073
(1980)Doi:10.1039/P19810000706
(1981)Doi:10.1021/jm00180a026
(1980)Doi:10.1021/jo049741z
(2004)Doi:10.1016/j.procbio.2010.02.006
(2010)Doi:10.1021/jo01303a014
(1980)