The first structural study on a cyclic tricoordinate phosphorochloridite and a pentacoordinate phosphorane based on 1,2,3,5-protected myo-inositol—a new conformation of 1,3,2-dioxaphosphorinane ring

Treatment of the phosphoramidite {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2P-NH-i-Pr)} with o-chloranil affords the first example of inositol-based pentacoordinate phosphorane {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2P-NH-i-Pr)(1,2-O2C6Cl4)} (9) (X-ray structure) with a trigonal bipyramidal geometry at phosphorus. The six-membered 1,3,2-dioxaphosphorinane ring with the inositol residue has an unusual boat conformation in 9 which is quite different from that found in unrestrained rings investigated before, but is similar to that of its PIII chloro precursor {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(O2PCl)} (X-ray structure). Also, a convenient and chromatography-free procedure for the protected myo-inositol derivative {myo-C6H6-2-[OC(O)Ph]-1,3,5-(O3CH)-4,6-(OH)2} is reported.

Graphical abstractSynthesis and X-ray structures of the first examples of a cyclic phosphorochloridite (7) and a pentacoordinate phosphorane (9) based on 1,2,3,5-protected myo-inositol that exhibit a new boat conformation for the 1,3,2-dioxaphosphorinane ring, are reported. A chromatography-free synthesis of the protected diol, benzoic acid 8,9-dihydroxy-2,4,10-trioxa-tricyclo[3.3.1∗3,7∗]dec-6-yl ester (6), is presented.Figure optionsDownload full-size imageDownload as PowerPoint slide