Reaction of aminocarbene complexes of chromium and tungsten 6. Rearrangements of and insertions of alkynes into aziridinylcarbene complexes

Abstract

Pentacarbonyl[(2-methylaziridinylxmethyl)carbenelchromium(O) ( 2a) reacts with LiBu followed by H 2O to regenerate the starting carbene complex. Treatment of the same reaction mixture with D 2O leads to the perdeuteromethyl carbene complex 2D3. However, addition of CH 3I instead of D 20 gives pentacarbonyl( N-methyl-2-aza-3-methylcyclopentylidene)chromium(O) ( 28) by ring opening followed by alkylation at nitrogen. The aziridinylcarbene complexes [(CO) 5 M = C( NCH(CH 3)C H 2)R 1 (M = Cr 1, R 1 = Me, 2a, R 1 = Ph, 2b, R 1 = cyclopropyl, 2c react with diphenylacetylene or phenylpropyne) to give 30a-c, 33 and 34 via double alkyne and single CO insertions. However, complex 2d (M = W, R 1 = Me) gave only trace amounts of the expected complex 30d. Treatment of 30a with pyridine led to the metal-free derivative 31. Complex 30b (R 1 = Ph) was fully characterized by X-ray diffraction.