| 18200585 |
Kumar NN, Swamy KC: Single diastereomers of unsymmetrical tris-spirocyclic cyclotriphosphazenes based on 1,1'-bi-2-naphthol--synthesis and structures. Chirality. 2008 Jun;20(6):781-9.
Diastereoselective synthesis and characterization of chiral unsymmetrical tris-spirocyclic cyclotriphosphazenes based on chiral 1,1'-bi-2-naphthol (BINOL) are reported. Specifically, the chiral compounds (-) N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](O-2,2'C (6) H (4)-C (6) H (4) O) Cl (2) [(-)-4] and (-) N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](OCH (2) CH (2) NMe)(2) [(-)-5] are prepared by starting with the chiral mono-spiro compound (-) N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)] Cl (4) [(-)-3]. Synthesis of four other chiral spirocyclics, N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](OCH (2) CH (2) NMe)(O-2,2'C (6) H (4)-C (6) H (4) O)[(-)-6 and (+)-6], N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](NMe (2))(4) [(-)-7], N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](O-2,2'C (6) H (4)-C (6) H (4) O)(NMeCH (2) CH (2) O H)(2) [(-)-8 and (+)-8], and N (3) P (3)[1,1'-O (2)(C (10) H (6))(2)](O-2,2'C (6) H (4)-C (6) H (4) O)[NHCH (2) CH (2) CH (2) Si (OEt)(3)](2) (9) is also reported herein. Compounds 4-6 are obtained in the solid state diastereoselectively and their X-ray structures have been determined and discussed. The diastereoselectivity is also shown by structural characterization of two distinct isomers in the case of 6 [(-)-6 and (+)-6, respectively] by starting with precursor of 3 having (R) or (S)-BINOL residue. The (1) H NMR spectra of 7 and 8 exhibit doublets with virtual coupling for the methyl protons, consistent with the chiral nature of the binaphthoxy residue. The potential of 9, which hydrolyzes readily in CDCl (3) solution, as a useful precursor for chiral polymer applications is highlighted. |
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