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| 用亚磷酸三乙酯代替三苯基膦所制得的磷Ylide与醛酮反应称为Wittig-Horner反应。该反应有两个优点:一是它容易和醛酮反应,有些有三苯基膦制备的磷叶立德,特别是当α碳上带有羰基时,比较稳定,不容易和酮带有,有时需加入苯甲酸作为催化剂。二是反应中的另一产物,O,O-二乙基磷酸钠溶于水,无需像三苯基膦的叶立德时,还需要分离三苯氧膦。三是磷酸酯的反应,立体选择性很强,产物主要是反式。 |
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594306435(金币+15, 翻译EPI+1): 谢谢 2011-04-16 18:58:17
| Triethyl phosphate which was instead of Triphenylphosphine was prepared for P-ylide . Wittig-Horner reaction was Defined as the reaction of Keto-Aldehyde and above P-ylide . This reaction had two advantages: The first was that it could react with Keto-Aldehyde easily , some P-ylide which was prepared by Triphenylphosphine , especially as there was carbonyl on α-Cedrene , it was Relatively stable and it could not be with ketone easily , sometimes it might be needed benzoic acid as catalyst . The second was that Another product of the reaction: O, O - diethyl sodium was soluble in water , Triphenylphosphine oxide did not need to be separated when P-ylide was prepared by Triphenylphosphine . The third was that the reaction of phosphoric ester had very strong stereoselectivity , and the product of the reaction was mainly antiform . |
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