33733-62-9Relevant academic research and scientific papers
Base-Induced 1,3-Sigmatropic rearrangement of mesitylphosphonium salts
Solomon, Sophia A.,Allen, Lucy K.,Dane, Sarah B. J.,Wright, Dominic S.
, p. 1615 - 1619 (2014)
Attempted synthesis of the ylide dianion [2,4,6-Me3C 6H2P(CHR)3]2- (2,4,6-Me 3C6H2 = mesityl, R = H or Me) by the reaction of mesitylphosphonium iodides [2,4,6-Me3C6H 2PR3]+I- (R = Me, 1; R = Et, 2) with tBuLi at reflux does not result in the anticipated deprotonation of the phosphorus-bonded R groups. Instead, quantitative 1,3-sigmatropic rearrangement occurs to give new benzylic phosphonium salts [(3,5-Me2C 6H3)CH2PR3]+I - (R = Me, 6; R = Et, 7), in which the phosphonium centre, the R 3P group, is transferred to an ortho-CH3 group. In situ 31P NMR spectroscopic studies show that the reaction is base-activated and stoichiometric with respect to tBuLi. DFT calculations support the conclusion that the rearrangement is thermodynamically favourable in the gas phase and in THF and show that the rearrangement is enthalpically driven. Copyright
Base-induced 1,3-sigmatropic rearrangement of mesitylphosphonium salts
Solomon, Sophia A.,Allen, Lucy K.,Dane, Sarah B. J.,Wright, Dominic S.
supporting information, p. 1615 - 1619 (2015/04/27)
Attempted synthesis of the ylide dianion [2,4,6-Me3C6H2P(CHR)3]2- (2,4,6-Me3C6H2 = mesityl, R = H or Me) by the reaction of mesitylphosphonium iodides [2,4,6-Me3C6H2PR3]+I- (R = Me, 1; R = Et, 2) with tBuLi at reflux does not result in the anticipated deprotonation of the phosphorus-bonded R groups. Instead, quantitative 1,3-sigmatropic rearrangement occurs to give new benzylic phosphonium salts [(3,5-Me2C6H3)CH2PR3]+I- (R = Me, 6; R = Et, 7), in which the phosphonium centre, the R3P group, is transferred to an ortho-CH3 group. In situ 31P NMR spectroscopic studies show that the reaction is base-activated and stoichiometric with respect to tBuLi. DFT calculations support the conclusion that the rearrangement is thermodynamically favourable in the gas phase and in THF and show that the rearrangement is enthalpically driven. Teaching an old dog new tricks: First synthesised in 1935, phosphonium salts [2,4,6-Me3C6H2PR3]+I- (2,4,6-Me3C6H2 = mesityl, R = Me or Et) exhibit an unexpected quantitative rearrangement in the presence of tBuLi, in which the phosphine group R3P is transferred to an ortho-CH3 position.
