REACTIVITY OF ORGANOZINC DERIVATIVES OF PHOSPHININES

The reactions of the 2-organozinc derivatives 1, 2, and 3 of 4,5-dimet hylphosphinine with electrophiles of phosphorus, arsenic, tin, copper, silver, and mercury are discussed. The reactions of 2 and 3 with arse nic trichloride furnished the monosubstitution products 4 and 5, respe ctively, which were not isolable in pure form. Reactions of 2 and 3 wi th phosphorus electrophiles were partially successful, but the monosub stitution products 8 and 11, respectively, were not formed selectively ; among the byproducts were 7, 9, and 10. Transmetalation reactions wi th tin electrophiles gave 13 (37%) and 16 (7%), which were isolated in pure form. Transmetalation of 2 with a copper salt furnished copper d erivative 17, which was trapped below -80 degrees C with a Michael acc eptor and chlorotrimethylsilane to give the 1,4-addition product 19. T his compound was obtained in nearly pure form in a yield of 20% relati ve to the 2-iodophosphinine 10. Transmetalation of 3 with a copper sal t furnished the copper derivative 20, which decomposed within 6 h at r oom 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 ou t to be rather unstable at room temperature. Transmetalation reactions with mercury salts were successful with 1, 2, and 3. The organomercur y derivative 22 obtained via 1 and 2, respectively, decomposed at room temperature, but was characterized by H-1, C-13, and P-31 NMR spectro scopies. The relatively stable organomercury derivative 23, obtained f rom 3, was isolated in a yield of 50% relative to 10.