The reactions of the 2-organozinc derivatives 1,
2, and 3 of 4,5-dimethylphosphinine
with
electrophiles of phosphorus, arsenic, tin, copper, silver, and mercury
are discussed. The
reactions of 2 and 3 with arsenic trichloride
furnished the monosubstitution products 4 and
5, respectively, which were not isolable in pure form.
Reactions of 2 and 3 with
phosphorus
electrophiles were partially successful, but the monosubstitution
products 8 and 11,
respectively, were not formed selectively; among the byproducts were
7, 9, and 10.
Transmetalation reactions with tin electrophiles gave
13 (37%) and 16 (7%), which were
isolated in pure form. Transmetalation of 2 with a
copper salt furnished copper derivative
17, which was trapped below −80 °C with a Michael
acceptor and chlorotrimethylsilane to
give the 1,4-addition product 19. This compound was
obtained in nearly pure form in a
yield of 20% relative to the 2-iodophosphinine 10.
Transmetalation of 3 with a copper salt
furnished the copper derivative 20, which decomposed within
6 h at room temperature. This
compound was also prepared via direct insertion of reactive Cu(0)
into 12. Transmetalations
with silver salts afforded the organosilver derivatives
21−21‘
‘. These silver species
turned
out to be rather unstable at room temperature. Transmetalation
reactions with mercury
salts were successful with 1, 2, and
3. The organomercury derivative 22 obtained
via 1 and
2, respectively, decomposed at room temperature, but was
characterized by 1H, 13C, and
31P
NMR spectroscopies. The relatively stable organomercury derivative
23, obtained from 3,
was isolated in a yield of 50% relative to 10.