Syntheses of Chiral Phosphazenes with Stereogenic Centers: NMR Behavior in the Presence of a Chiral Solvating Agent

Abstract

ABSTRACTThe condensation reactions of tetrachloro mono (1 and 2) and bisferrocenyl spirocyclotriphosphazenes (3–5) with morpholine in tetrahydrofuran gave the partly morpholino‐substituted ferrocenylphosphazenes. When the reactions were carried out with equal amounts of 1–5 and morpholine, the mono‐substituted ferrocenylphosphazenes (1a, 3a–5a) formed as the major product. While the reactions were made with 1 equiv of 1–5 and 2 equiv of morpholine, the corresponding geminal–phosphazenes (1b–5b) were isolated. In addition, the condensation reactions of 1 equiv of 1–5 and 3 equiv of morpholine resulted in the formation of di‐(1b–5b), tri‐(2c–5c), and tetra‐substituted phosphazenes. The tri‐substituted compounds were isolated as major products. Some new phosphazenes have stereogenic P center(s). The stereogenic properties of 1a and 2c were investigated using 31P nuclear magnetic resonance (NMR) spectroscopy in the presence of the chiral solvating agent; (S)‐(+)‐2,2,2‐trifluoro‐1‐(9′‐anthryl)ethanol. The structures of all the phosphazenes were characterized by one‐dimensional 1H, 13C, and 31P NMR, and two‐dimensional heteronuclear single quantum coherence spectral data. The salient spectral properties of the phosphazenes were presented.