Design of a new axially chiral molecule by conformational fixation: 2,6-diphospha- and 2,6-diarsaspiro[3.3]heptanes

作者：Naruse Yuji^*; Kugiya Yuuki

来源：Tetrahedron: Asymmetry , 2013, 24(4): 169-171.

DOI：10.1016/j.tetasy.2013.01.008

We have designed a new axially chiral diphosphine that shows conformational rigidity: 2,6-diphosphaspiro[3.3]heptane 2a. This molecule has axial asymmetry due to puckering of the two phosphetane ring systems. Although its nitrogen congener 2,6-diazaspiro[3.3]heptane la is easily racemized, 2,6-diphosphaspiro[3.3]heptane 2a does not racemize at ambient temperature because the lone pairs on the phosphorus atoms have a strong s-character, which results in a high barrier to inversion at the phosphorus, that is, a high barrier to racemization. We also calculated the properties of the diarsa congener 3a and predicted that it also exhibits axial chirality and that it can be separated into enantiomers at ambient temperature.

• 出版日期2013-2-28