10.1021/jo061659b.s003
Jamal Lasri
Jamal
Lasri
M. Adília Januário Charmier
M.
Adília Januário Charmier
Matti Haukka
Matti
Haukka
Armando J. L. Pombeiro
Armando
J. L. Pombeiro
Stereospecific Synthesis of Polysubstituted <i>E</i>-Olefins by Reaction of
Acyclic Nitrones with Free and Platinum(II) Coordinated
Organonitriles
American Chemical Society
2007
4 b R
complex
Acyclic Nitrones
2R
13 C
microwave irradiation
195 Pt NMR spectroscopies
MeC
3C
CO 2Me 1 b R
oxadiazoline
analyses
acyclic nitrones
alkene 3
refluxing CH 2Cl
NC
Stereospecific Synthesis
1 H
CO 2Me Cl
5 c
6H
CH 2Cl 5
CO 2Me
NCCH
FAB
1 c R
IR
2007-02-02 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Stereospecific_Synthesis_of_Polysubstituted_i_E_i_Olefins_by_Reaction_of_Acyclic_Nitrones_with_Free_and_Platinum_II_Coordinated_Organonitriles/3029491
Free nitriles NCCH<sub>2</sub>R (<b>1a</b> R = CO<sub>2</sub>Me, <b>1b</b> R = SO<sub>2</sub>Ph, and <b>1c</b> R = COPh) with an acidic α-methylene
react with acyclic nitrones <sup>-</sup>O<sup>+</sup>N(Me)C(H)R‘ (<b>2a</b> R‘ = 4-MeC<sub>6</sub>H<sub>4</sub> and <b>2b</b> R‘ = 2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>), in
refluxing CH<sub>2</sub>Cl<sub>2</sub>, to afford stereoselectively the <i>E</i>-olefins (NC)(R)CC(H)R‘ (<b>3a</b><b>−</b><b>3c</b> and <b>3a</b>‘<b>−</b><b>3c</b>‘),
whereas, when coordinated at the platinum(II) <i>trans</i>-[PtCl<sub>2</sub>(NCCH<sub>2</sub>R)<sub>2</sub>] complexes (<b>4a</b> R = CO<sub>2</sub>Me
and <b>4b</b> R = Cl), they undergo cycloaddition to give the (oxadiazoline)-Pt<sup>II</sup> complexes (R = CO<sub>2</sub>Me, Cl and R‘ = 4-MeC<sub>6</sub>H<sub>4</sub>, 2,4,6-Me<sub>3</sub>C<sub>6</sub>H<sub>2</sub>) (<b>5a-5d</b>).
Upon heating in CH<sub>2</sub>Cl<sub>2</sub>, <b>5a</b> affords the corresponding alkene <b>3a</b>. The reactions are greatly accelerated
when carried out under focused microwave irradiation, particularly in the solid phase (SiO<sub>2</sub>), without
solvent, a substantial increase of the yields being also observed. The compounds were characterized
by IR and <sup>1</sup>H, <sup>13</sup>C, and <sup>195</sup>Pt NMR spectroscopies, FAB<sup>+</sup>-MS, elemental analyses and, in the cases
of the alkene (NC)(CO<sub>2</sub>Me)CC(H)(4-MeC<sub>6</sub>H<sub>4</sub>) <b>3a</b> and of the oxadiazoline complex <b>5c</b>, also by X-ray diffraction analyses.