Synthesis and Isolation of Homeomorphous Isomers of P-Containing Cryptands

Abstract

The novel isomeric phosphite cryptands 2, 3, and 4 could be synthesized by a simple one-pot tripod capping method starting from bisphenol 1 and PCl3. The assembling of five components led to the formation of a macrobicyclic structure, which probably requires an appropriate preorganization of the reactants. In contrast to the NMR spectra of 2, 3, and 4 in solution, the X-ray structures of 2 and 3 reveal that these molecules have no C3 symmetry in the solid state. In the 31P NMR spectra, both in- and out-P atoms have remarkably different chemical shifts due to a distorted geometry around the in-phosphorus. Phosphorus atoms in the inposition have a decreased reactivity. They are, therefore, more slowly oxidized by cumene hydroperoxide than out-P atoms. A stepwise synthesis was developed for phosphite/phosphatecryptands (5, 7, 9, and 15) via the monoprotected bisphenol 11 and the phosphate 14. In addition, the cylindrical macrotricycle 16 was isolated as a mixture of diastereomers from the crude product of this reaction.

Invertomers of Fullerenophosphates

“…This form of in / out ‐isomerism has been observed for macrobicyclic phosphates such as 22 – 24 (Figure 1). 14 In fact, it is a rather common structural feature of phosphorus containing macrocycles, which is also found for phosphites, phosphines, and phosphine oxides 15…”

Phosphorus-containing macrocyclic compounds: synthesis and properties

“…Phosphite cryptands were synthesized by the one-step method, the so-called double-capping reaction. 27,38,39 The reaction of sterically unhindered bisphenol 45 with PCl 3 in the presence of triethylamine in toluene at 20 8C in moderately dilute solution affords three possible homeomorphic isomers 46 (out,out), 47 (in,in) and 48 (in,out) in a ratio of 2 : 1 : 2 in a total yield of 15% (Scheme 15) { Low yields of the products in this reaction were quite expected because the formation of the cage structure involves the formation of six new bonds. This explains why only a few examples of the double-capping synthesis are known.…”

“…Based on the results of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, one of the fractions was determined as a mixture of isomers of macrobicycle 65 having a cylindrical structure (yield was 8% of the total amount of the macrocycles). 27,38 The single-capping strategy was further developed in the studies, 43,44 where the synthesis of phosphine oxide derivatives of bicyclic cryptands containing ever larger cavities was documented.…”

Synthesis of arylenephosphamacrocycles using tri- and pentavalent phosphorus compounds

“…26 Analysis of the structures of cryptands 25 revealed thè in ± out' isomerism. All three stereoisomers were chromatographically separated.…”