Synthesis and Structures of New Oxidation/ Cycloaddition Products of λ 3 ‐Cyclodiphosphazanes

Reaction of the cyclodiphosphazane [(OC 4 H 8 N)P(μ‐N‐ t ‐Bu) 2 P(HN‐ t ‐Bu)] ( 1 ) with an equimolar quantity of diisopropyl azodicarboxylate afforded the phosphinimine product [(OC 4 H 8 N)P(μ‐N‐ t ‐Bu) 2 P=N‐ t ‐Bu)(N(CO 2 ‐ i ‐Pr)NHCO 2 ‐ i ‐Pr] ( 6 ) having a P III ‐N‐P V skeleton. Similar products [( t ‐BuNH)P(μ‐N‐ t ‐Bu) 2 P=N‐ t ‐Bu)(N(CO 2 Et)NHCO 2 Et] ( 7 ) and [(CO 2 ‐ i ‐Pr)HNN(CO 2 ‐ i ‐Pr)]( t ‐BuN=P(μ‐N‐ t ‐Bu) 2 POCH 2 CMe 2 CH 2 O[P(μ‐N‐ t ‐Bu) 2 P=N‐ t ‐Bu)(N(CO 2 ‐ i ‐Pr)NH(CO 2 ‐ i ‐Pr)] ( 8 ) were spectroscopically characterized in the reaction of [( t ‐BuNH)P‐N‐ t ‐Bu] 2 ( 2 ) and [( t ‐BuNH)P(μ‐N‐ t ‐Bu) 2 POCH 2 CMe 2 CH 2 OP(μ‐N‐ t ‐Bu) 2 P(NH‐ t ‐Bu)] ( 3 ) with diethyl‐ and diisopropyl azodicarboxylate, respectively. By contrast, the reaction of [(μ‐ t ‐BuN)P] 2 [O‐6‐ t ‐Bu‐4‐Me‐C 6 H 2 ] 2 CH 2 ( 4 ) and [(C 5 H 10 N)P‐μ‐N‐ t ‐Bu] 2 ( 5 ) with diisopropyl azodicarboxylate afforded the mono‐ and bis‐oxidized compounds [(O)P(μ‐N‐ t ‐Bu) 2 P][O‐6‐ t ‐Bu‐4‐Me‐C 6 H 2 ] 2 CH 2 ( 9 ) and [(C 5 H 10 N)(O)P‐μ‐N‐ t ‐Bu] 2 ( 10 ), respectively. Oxidative addition of o ‐chloranil to 7 and its DIAD analogue [( t ‐BuNH)P(μ‐N‐ t ‐Bu) 2 P=N‐ t ‐Bu)(N(CO 2 ‐ i ‐Pr)NHCO 2 ‐ i ‐Pr] ( 11 ) afforded [(C 6 Cl 4 ‐1, 2‐O 2 )( t ‐BuNH)P(μ‐N‐ t ‐Bu) 2 P=N‐ t ‐Bu)(N(CO 2 R)NHCO 2 R] [R = Et ( 12 ) and i ‐Pr ( 13 )] containing tetra‐ and pentacoordinate P V atoms in the cyclodiphosphazane ring. The structures of 6 , 9 , 12 and 13 have been confirmed by X‐ray structure determination. For comparison, the X‐ray structure of the double cycloaddition product [(C 6 Cl 4 ‐1, 2‐O 2 )( t ‐BuNH)PN‐ t ‐Bu] 2 ( 14 ), obtained from the reaction of 2 with two mole equivalents of o ‐chloranil is also reported.