Mechanism of the Exchange Reaction of Halodiazirines with Nucleophiles Revisited. Synthesis of Neutral, Mono- or Dicationic 4−16-Membered Phosphorus Heterocycles

Trimethyl-, diphenylmethyl-, triphenyl-, diphenylthienyl-, and
bis(dimethylamino)(isopropylthio)phosphine
react with bromophenyldiazirine (1) giving cationic
N,N‘-bis(phosphine) adducts
2a−c, 7, and 8
in 83−95% yields.
Depending on the experimental conditions used, addition of
1,2-bis(diphenylphosphino)ethane to 1 leads to
dicationic
14- and monocationic seven-membered heterocycles 3 (90%
yield) and 4 (60% yield) or cationic
N,N‘-bis(diphosphine)
adduct 5 (86% yield); similarly, when
diphenyl(isopropylthio)phosphine is used, competitive
reactions occur, leading
to cationic five-membered heterocycle 9 (34% yield) and/or
N,N‘-Bis(diphosphine) adduct 10
(65% yield). 1,3-bis(diphenylphosphino)propane also reacts with 1, affording
dicationic 16-membered heterocycle 6 (75% yield).
Addition
of bis(diisopropylamino)(trimethylstannyl)phosphine to
1 gives rise to a mixture of
N-[(trimethylstannyl)imino]bis(diisopropylamino)bromophosphorane (11) (32%),
2,2-bis(diisopropylamino)-4-phenyl-1,3,2λ5-diazaphosphete
(12)
(26% yield), 1,3,5,2λ5-triazaphosphinine 13
(3% yield), benzonitrile (35%), and bromotrimethylstannane (60%).
The
mechanisms involved in these reactions are studied.