Beiträge zur Chemie des Bors, 221. Kinetische und thermodynamische Produktkontrolle bei der Addition von HX‐Verbindungen an ein Amino‐phosphanylimino‐boran R 2 NBNPR 2 ′

Contributions to the Chemistry of Boron, 221 [1] . — Kinetic and Thermodynamic Product Control in the Addition of HX Compounds to an Amino Phosphanylimino Borane R 2 NBNPR 2 ′ The reaction of equimolar amounts of HI with tmp=BNP t Bu 2 ( 3 ) (tmp = 2,2,6,6‐tetramethylpiperidino group) in an unpolar solvent yields the phosphonium salt [tmp‐BNPH t Bu 2 ]I ( 4 ). No such well‐defined reaction was observed with triflic or tetrafluoroboric acid. In contrast, HCl reacts with 3 to produce a mixture of tmp‐B(Cl)‐NH‐P t Bu 2 ( 5 ) and tmp—B(Cl)—NPH t Bu 2 ( 6 ). On heating or on standing at ambient temperature the unique proton of 5 migrates from the N to the P atom with formation of 6 , which, therefore, is thermodynamically more stable than 5 .