Synthesis and isolation of homeomorphous isomers of p-containing cryptands

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 s tructure, which probably requires an appropriate preorganization of the rea ctants. In contrast to the NMR spectra of 2, 3, and 4 in solution, the X-ra y structures of 2 and 3 reveal that these molecules have no C-3 symmetry in the solid state. In the P-31 NMR spectra, both in- and out-P atoms have re markably different chemical shifts due to a distorted geometry around the i n-phosphorus. Phosphorus atoms in the in- position have a decreased reactiv ity. They are, therefore, more slowly oxidized by cumene hydroperoxide than out-P atoms. A stepwise synthesis was developed for phosphite/phosphate-cr yptands (5, 7, 9, and 15) via the monoprotected bisphenol 11 and the phosph ate 14. In addition, the cylindrical macrotricycle 16 was isolated as a mix ture of diastereomers from the crude product of this reaction.