Comparative Study of the Reactions of Two Alkynes and an Alkene with Chiral Cyclopalladated Complexes Derived from N,N-Dimethyl-α-(2-naphthyl)ethylamine and N,N-Dimethyl-α-methylbenzylamine:  Insertion or Cycloaddition

The chiral cyclopalladated complexes containing coordinated 3,4-dimethyl-1-phenylphosphole, DMPP, and an N-donor ligand, ( S C )- 1 or ( S C )- 3, reacted with dimethylacetylene dicarboxylate, DMAD, and diphenylacetylene to produce exclusively the insertion products ( S C )- 2, ( S C )- 4, ( S C )- 5, and ( S C )- 6, respectively, although [4+2] Diels−Alder cycloaddition reactions between DMAD or diphenylacetylene and coordinated DMPP were possible. N -Phenylmaleimide underwent [4+2] Diels−Alder cycloaddition to the coordinated DMPP in the insertion product ( S C )- 2 to form two stereoisomers of ( S C )- 7 in a 1.55:1 ratio. However, under similar conditions the insertion product ( S C )- 4 did not react with N -phenylmaleimide. Complexes ( S C )- 1 and ( S C )- 3 reacted with N -phenylmaleimide to give only one enantiomer of the [4+2] Diels−Alder cycloaddition product, although two diastereomeric products were possible in each reaction. The cycloaddition product ( S C )- 8 reacted with DMAD to give only one stereoisomer of the insertion product ( S C )- 7, but under similar conditions the cycloaddition product ( S C )- 9 did not react with DMAD. New complexes were characterized by elemental analyses, physical properties, polarimetry, 1 H, 1 H{ 31 P}, 13 C{ 1 H}, and 31 P{ 1 H} NMR spectroscopy, and in several cases X-ray crystallography.