Unexpected ring opening of cycloaminocarbene complexes of chromium upon alkyne insertion reactions

Article abstract of DOI:10.1016/0022-328X(88)87082-7

Aminocarbenechromium complexes of the general structure (CO)5Cr=C(R)N(CH2)nXCH2 (N = 0, X = CH2; n = 1, X = CH2; n = 1 X = CH=CH; n = 2 X = CH=CH; R = CH3, Ph) react with alkynes to give insertion of one or two molecules of alkyne and one molecule of CO, and C-N bond cleavage, new polycyclic heterocycles.The reactions of the pyrroline-, the tetrahydropyridine-, the pyrrolidine- and the methylaziridine-substituted complexes are mainly considered, and the results of X-ray structural studies of the new products are presented.The mechanism of the rearrangement of a 1,5 dipole is discussed.