CYCLIC AMINOPHOSPHITES AND AMINOPHOSPHORANES POSSESSING 6-MEMBERED AND HIGHER-MEMBERED RINGS - A COMPARATIVE-STUDY OF STRUCTURE AND REACTIVITY

Aminophosphoranes 2 and 4-9 with a cyclohexylamino substituent and rin g sizes varying from five to eight have been synthesized by oxidative addition reactions of cyclic aminophosphites with diols or 1,2-diketon es. The reactivities of these phosphoranes are compared with those of tile corresponding cyclic aminophosphites. The difference in hydrolyti c pathways between amino- and analogous phenoxyphosphoranes is discuss ed. X-ray structures of two sets of compounds, (a) (C6H11NH)P(OCH2CMe2 CH2O) (1) and (C6H11NH)P(OCH2CMe2CH2O)(1,2-O2C6Cl4) (2) and (b) (C6H11 NH)P{O-(t-Bu)(2)C6H2)(2)CH2} (3) and (C6H11NH)P{(O-(t-Bu)(2)C6H2)(2)CH 2}(1,2-O2C6H4). 1/2Et(2)O (4 . 1/2Et(2)O) have been determined and geo metrical parameters compared between the P(III) and the corresponding P(V) compounds. In 1, the six-membered ring has a chair conformation w ith the amino group axial; in 2, the six-membered ring is located apic al-equatorial in a trigonal bipyramidal geometry and has a boat confor mation. The eight-membered ring has a boat-chair conformation in 3, wh ereas the same ring has a tub conformation in 4.