- Identification of a four-center intermediate in a Grignard addition reaction to a P-S bond
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The reaction between tert-butylmagnesium chloride (or tert-pentylmagnesium chloride) and the particular phosphorus-sulfur bond of a benzothiadiphospholic system showed, for the first time, evidence of formation of intermediates with a four-center structure. The possibility, for the phosphorus atom, to have very stable hypervalent coordinations makes it possible to observe its hypervalent states during the course of a reaction. The benzothiadiphosphole, with its bicyclic folded structure, further stabilizes the hypervalent coordinations thus making the intermediates sufficiently stable to be detected during the course of the reaction by 31P NMR spectroscopy, which revealed the nature and the stability of the species involved in this reaction, carried out also using other Grignard reagents.
- Baccolini, Graziano,Boga, Carla,Mazzacurati, Marzia
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p. 12595 - 12600
(2008/03/14)
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- Highly atom-economic one-pot formation of three different C-P bonds: General synthesis of acyclic tertiary phosphine sulfides
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The reaction of benzothiadiphosphole 1 with an equimolar mixture of R 1MgBr and R2MgBr gave intermediate A′, which, after only 4-5 min, was treated with an equimolar amount of R3MgBr, giving the asymmetric phosphine PR1R2R3 in 45% overall yield (75-80% yield when R1 = R2 and 85-90% yield when R1 = R2 = R3) and the byproduct 6 in 90% yield. The treatment of 6 with PCl3 quantitatively regenerates the starting reagent 1. Treatment of the phosphines with elemental sulfur gave the corresponding sulfides.
- Baccolini, Graziano,Boga, Carla,Mazzacurati, Marzia
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p. 4774 - 4777
(2007/10/03)
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