A study of the ring-opening of lactides and related cyclic esters by Ph2SnX2 and Ph3SnX compounds (X?=?NMe2, OR)Electronic supplementary information (ESI) available: preparation and characterization data for Ar3SnX, Ph2SnNMe2 and Ph2Sn(OPri)2 compounds [X?=?NMe2, OMe, OPri, OBut, OPh, OCH(CF3)2, PPh
A study of the ring-opening of lactides and related cyclic esters by Ph2SnX2 and Ph3SnX compounds (X?=?NMe2, OR)Electronic supplementary information (ESI) available: preparation and characterization data for Ar3SnX, Ph2SnNMe2 and Ph2Sn(OPri)2 compounds [X?=?NMe2, OMe, OPri, OBut, OPh, OCH(CF3)2, PPh
复制标题
Ph2SnX2 和 Ph3SnX 化合物 (X?=?NMe2, OR) 丙交酯和相关环酯开环的研究提供电子补充信息 (ESI)：Ar3SnX、Ph2SnNMe2 和 Ph2Sn(OPr)2 化合物的制备和表征数据
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Ewan E. Delbridge
中科院分区：
文献类型：
--
作者：
M. Chisholm;Ewan E. Delbridge
在初始开环事件中，Ph3SnX与l -丙交酯的反应顺序为X=NMe2 ~ OMe > OPri>OBut。甲基取代的1,4-二恶烷-2,5-二酮的开环速率随甲基取代而降低，而3,3,6,6-四甲基-1,4-二恶烷-2,5-二酮的开环速率未见变化。通过对Ph3SnOPri与l -丙烯酰胺反应的研究，确定了活化参数ΔH≠=13(1)kcal mol−1和ΔS≠=−37(3)eu。Ph3SnNMe2与环酯和碳酸丙烯在低温下反应，得到可分离的开环产物。化合物Ph3Sn[OCHMeC(O)OCHMeC(O)X]（其中X=NMe2, OMe）在室温下在溶液中不稳定，通过酯交换反应生成Ph3Sn[OCHMeC(O)X]和Ph3Sn[OCHMeC(O)]nX（其中n≥3），以及由于苯基/OR基团转移（即Ph4Sn）而产生的其他少量产物。l -丙交酯通过开环反应生成Ph2Sn[OCHMeC(O)NMe2]2。Ph2Sn[OCHMeC(O)OPri]2与l -丙交酯反应也形成了相应的化合物Ph2Sn[OCHMeC(O)OPri]2，但对l -丙交酯进一步开环更不稳定。
Ph3SnX reacts with L-lactide in the order X=NMe2∼OMe≫OPri>OBut in the initial ring-opening event. The rate of ring-opening of methyl substituted 1,4-dioxane-2,5-diones decreases with methyl substitution and ring-opening of 3,3,6,6-tetramethyl-1,4-dioxane-2,5-dione is not observed. From studies of the reaction between Ph3SnOPri and L-lactide the activation parameters ΔH≠=13(1) kcal mol−1 and ΔS≠=−37(3) eu have been determined. Ph3SnNMe2 reacts with cyclic esters and propylene carbonate at low temperatures to give isolable ring-opened products. The compound Ph3Sn[OCHMeC(O)OCHMeC(O)X] (where X=NMe2, OMe) are labile in solution at room temperature, yielding Ph3Sn[OCHMeC(O)X] and Ph3Sn[OCHMeC(O)]nX, where n≥3, by transesterification, along with other minor products due to phenyl/OR group transfer (i.e., Ph4Sn). Ph2Sn(NMe2)2 and L-lactide react to give Ph2Sn[OCHMeC(O)NMe2]2 by ring-opening of L-lactide followed by rapid amidation. A related compound, Ph2Sn[OCHMeC(O)OPri]2, is also formed in the reaction between Ph2Sn(OPri)2 and L-lactide but is more labile toward further ring-opening of L-lactide.