Concerted C-N and C-H Bond Formation in a Magnesium-Catalyzed Hydroamination
| Title | Concerted C-N and C-H Bond Formation in a Magnesium-Catalyzed Hydroamination |
| Publication Type | Journal Article |
| Year of Publication | 2010 |
| Authors | Dunne JF, Fulton DB, Ellern A, Sadow AD |
| Journal Title | Journal of the American Chemical Society |
| Volume | 132 |
| Pages | 17680-17683 |
| Date Published | 12/22 |
| ISBN Number | 0002-7863 |
| Accession Number | ISI:000285429800013 |
| Keywords | alkenes, alkyl derivatives, amido bond, aminoalkene, complexes, insertion, internal alkynes, intramolecular hydroamination, mechanism, unprotected amino olefins |
| Abstract | Coordinatively saturated To(M)MgMe (1; To(M) = tris(4,4-dimethyl-2-oxazolinyl)phenylborate) is an active precatalyst for intramolecular hydroamination/cyclization at 50 degrees C. The empirical rate law of -d[substrate]/dt = K-obs[Mg](1)[substrate](1) and Michaelis-Menten-type kinetics are consistent with a mechanism involving reversible catalyst-substrate association prior to cyclization. The resting state of the catalyst, To(M)MgNHCH(2)CR(2)CH(2)CH=CH2 [R = Ph, Me, -(CH2)(5)-], is isolable, but isolated magnesium amidoalkene does not undergo unimolecular cyclization at 50 degrees C. However, addition of trace amounts of substrate allows cyclization to occur. Therefore, we propose a two-substrate, six-center transition state involving concerted C-N bond formation and N-H bond cleavage as the turnover-limiting step of the catalytic cycle. |
| URL | <Go to ISI>://000285429800013 |
| DOI | 10.1021/Ja108881s |
| Alternate Journal | J Am Chem Soc |
