41845-30-1Relevant articles and documents
High- and low-spin chelate complexes of iron featuring κ-C,X-CH2C6H4X (X?= NMe2, PMe2, PPh2) and κ-C,P-CH2PMe2 ligands
Jacobs, Brian P.,Wolczanski, Peter T.,MacMillan, Samantha N.
, p. 132 - 139 (2017)
Several C,X-chelate complexes of iron were generated via standard metathetical procedures. Treatment of FeCl2 and LnFeCl2 (L = Me2IPr, n = 1; PMe3, n = 2) with anionic equivalents o-LiCH2C6H4NMe2, o-LiCH2C6H4PPh2, and LiCH2PMe2 led to the preparation of [Fe(o-CH2C6H4NMe2)]2(κ-μ-CH2,N-o-CH2C6H4NMe2)2 (1, X-ray), [fac-Fe(κ-C,P-o-CH2C6H4PPh2)3][Li(TMEDA)2] (2, X-ray), (Me2IPr)Fe(CH2C6H4-o-NMe2)2 (3-C,N), [(Me2IPr)2Fe](μ-κ-C,P-CH2PMe2)2[Fe(κ-C,P-CH2PMe2)2] (4, X-ray), and (PMe3)2Fe(κ-C,P-CH2PMe2)2 (5). CH-Bond activation of cis-(Me3P)4FeMe2 with o-CH3C6H4PMe2 led to the generation of trans,cis-(PMe3)2Fe(κ-C,P-CH2C6H4-o-PMe2)2 (6). Exposure of these compounds to [Cp2Fe][PF6], a 1e? oxidant, or AdN3, here construed as a 2e? oxidant, led to degradation in all cases, usually with the generation of carbon-carbon coupled ligands as byproducts. The inability of these systems to permit access to higher iron oxidation states is discussed.
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.
