Reactions of N-Methylated Amino Acids and Benzylammonium Ions with P73- and As73-: Unusual Stereospecific Alkyl Group Transfers in the Synthesis of R2P7- and R2As7- Ions
Reactions of N-Methylated Amino Acids and Benzylammonium Ions with P73- and As73-: Unusual Stereospecific Alkyl Group Transfers in the Synthesis of R2P7- and R2As7- Ions
复制标题
N-甲基化氨基酸和苯甲基铵离子与 P73- 和 As73- 的反应：R2P7- 和 R2As7- 离子合成中异常的立体特异性烷基转移
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
B. Eichhorn
中科院分区：
文献类型：
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作者：
Sundeep P. Mattamana;Kumpeeh Promprai;and James C. Fettinger;B. Eichhorn
E73-（其中E = P（1）或As（2））的乙二胺（en）溶液与过量的（PhCH 2）Me 3 NBr反应，以良好的产率得到NMe 3和（PhCH 2）2 E7-离子的单一非对映体，其中E = P（3）或As（4）。[PPh 4]3和[K（2，2，2-crypt）]4盐的X-射线晶体结构表明，两种阴离子都具有空间上有利的对称结构。1的DMF溶液还与N-甲基化氨基酸的乙酯（EtOCO 3）Me 3 N+反应，其中R = H（甘氨酸）或Me（丙氨酸），得到（EtOCO 3）2 P7-离子，其中R = H（7）或Me（8）。当R不是质子时，Me+转移得到已知的Me 2 P7-离子（5）与（EtOCO 3）+转移竞争，使得5优于8的形成（5：8 = 2.5：1），但对于R = H（5：7 = 1：48），5仅为痕量杂质。进行丙氨酸酯的R和S对映异构体的反应以探测这些反应中碳上的立体化学，但是8的三种不同的非对映异构体（即，（R，R）-或（S，S）-、（R，S）-和（S，R）-（EtOCO 3）_2P_7-）均为不饱和的。
Ethylenediamine (en) solutions of E73-, where E = P (1) or As (2), react with excess (PhCH2)Me3NBr to give NMe3 and a single diastereomer of the (PhCH2)2E7- ions, where E = P (3) or As (4), in good yields. X-ray crystal structures of the [PPh4]3 and [K(2,2,2-crypt)]4 salts showed that both anions adopt the sterically favored symmetrical structure. DMF solutions of 1 also react with ethyl esters of N-methylated amino acids, (EtOCOCHR)Me3N+, where R = H (glycine) or Me (alanine), to give (EtOCOCHR)2P7- ions where R = H (7) or Me (8). The transfer of Me+ to give the known Me2P7- ion (5) is competitive with (EtOCOCHR)+ transfer when R is not a proton such that 5 is favored over the formation of 8 (5:8 = 2.5:1), but 5 is only a trace impurity for R = H (5:7 ≈ 1:48). Reactions of R and S enantiomers of the alanine esters were conducted to probe the stereochemistry at carbon in these reactions, but the three different diastereomers of 8 (i.e., (R,R)- or (S,S)-, (R,S)-, and (S,R)-(EtOCOCHR)2P7-) were indistinguis...