Demir Ayhan S, Emrullahoglu Mustafa, Pirkin Eser, Akca Nazmiye
Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey.
J Org Chem. 2008 Nov 21;73(22):8992-7. doi: 10.1021/jo801818p. Epub 2008 Oct 25.
Acyl phosphonates with alpha-halo ketones in the presence of bases at room temperature afford cis- and trans-epoxyphosphonates in good chemical yields and high selectivities using different bases. The diastereoselectivity of this reaction is easily controlled by changing the base. Changing the base from Cs2CO3 to DBU changed the diastereomeric ratio (trans/cis) from 3/2 to 9/1. Moreover, the treatment of the trans isomer with DBU showed a complete conversion to the corresponding cis isomer.
在室温下，酰基膦酸酯与α-卤代酮在碱的存在下，使用不同的碱可高产率且高选择性地得到顺式和反式环氧膦酸酯。通过改变碱可以很容易地控制该反应的非对映选择性。将碱从碳酸铯改为1,8-二氮杂双环[5.4.0]十一碳-7-烯（DBU），非对映体比例（反式/顺式）从3/2变为9/1。此外，用DBU处理反式异构体可完全转化为相应的顺式异构体。
