- Donor-unsupported Phosphanylmethanides Li[CH2PR2] (R = tBu, Ph) - Crystal Structure of Li[CH2PtBu2] Solved by XRPD and DFT-D Calculations
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The solvent-free methyllithium derivatives Li[CH2PR2] (R = tBu, Ph) were prepared via the reaction of CH3PR2 with Li[tBu]. It should be noted that the deprotonation of CH3PtBu2 with Li[tBu] occurred at 60 C, whereas Li[CH2PPh2] was already formed from CH3PPh2 with Li[tBu] at ambient temperature. The structure determination of di-tert-butylphosphanylmethyllithium was performed by high resolution X-ray powder diffraction analysis at different temperatures. This led to two possible structure solutions with similar quality criteria (space groups Iba2 and I2/a). Therefore CASTEP DFT-D calculations were applied to verify the correct crystal structure. The solid-state structure of di-tert-butylphosphanylmethyllithium consists of alternating edge-sharing six- and four-membered rings, which form a polymeric, infinite double-chain along the crystallographic c axis in the monoclinic space group I2/a. Two Li[CH2PtBu2] units connected via an inversion center form a six-membered Li2C2P2 ring in the chair conformation. The nearly flat four-membered Li2C2 ring, is oriented perpendicularly to the twofold axis.
- Fink, Lothar,Samigullin, Kamil,Bodach, Alexander,Alig, Edith,Wagner, Matthias,Lerner, Hans-Wolfram
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- Neutral Fe(iv) alkylidenes, including some that bind dinitrogen
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Neutral, formally Fe(iv) alkylidene species are sought as plausible olefin metathesis catalysts, and the synthesis of several is described herein. The complexes are prepared via nucleophilic attack (Nu = MeLi, PhCH2K, 2-picolyllithium, Me2PCH2Li, MePhPCH2Li, Ph2PCH2Li) at the imine of cationic [mer-{κ-C,N,C-(C6H4-yl)-2-CH=N(2-C6H4-C(iPr)=)}Fe(PMe3)3][B(3,5-CF3-C6H3)4]. In contrast, MeMgCl and mesityllithium displaced and deprotonated bound PMe3, respectively. Structural details are provided for mer-{κ-C,N,C-(C6H4-yl)-2-CH(Bn)N(2-C6H4-C(iPr)=)}Fe{trans-(PMe3)2}N2 and {κ-C,N,C,P-(C6H4-yl)-2-CH(CH2PMe2)N(2-C6H4-C(iPr)=)}Fe(PMe3)2.
- Lindley, Brian M.,Jacobs, Brian P.,MacMillan, Samantha N.,Wolczanski, Peter T.
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supporting information
p. 3891 - 3894
(2016/03/16)
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- Phosphine-Catalyzed Asymmetric Umpolung Addition of Trifluoromethyl Ketimines to Morita–Baylis–Hillman Carbonates
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A novel phosphine-catalyzed, highly enantioselective umpolung addition of trifluoromethyl ketimines to Morita–Baylis–Hillman carbonates was developed and it provides facile access to optically active trifluoromethyl amines with a chiral tertiary stereocenter under mild reaction conditions. The salient features of this reaction include general substrate scope, mild reaction conditions, good yields, high enantioselectivity, ease of scale-up to gram scale, and further transformations of the products.
- Chen, Peng,Yue, Zhenting,Zhang, Junyou,Lv, Xi,Wang, Lei,Zhang, Junliang
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supporting information
p. 13316 - 13320
(2016/10/30)
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- SYNTHESIS OF SOME FUNCTIONALIZED PHOSPHINOCARBOXYLIC ACIDS
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Various functionalized phosphinocarboxylic acids have been prepared by a number of complementary methods.Reactions of relatively electron-poor secondary phosphides with electron-rich halocarboxylates in liquid ammonia give high yields of phosphinocarboxylates.The substitution reactionmay proceed by a classical SN2 mechanism or by an SN rad mechanism.Reduction of the carboxilate can be a deleterious side reaction in the preparation of phosphinoacetic acids.Several phosphinopropionic acids are prepared by the Michael adition of diphenylphosphine to unsaturated esters.A valuable method proved to be the reaction of dichlorophosphinoacetic ester with functionalized organometallic reagents. Key words: Phosphine; carboxylic acid; ligand; functionalized; synthesis; NMR data.
- van Doorn, J. A.,Meijboom, N.
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p. 211 - 222
(2007/10/02)
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- Reactions of lithium with Dimethylfulvene
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lithium reacts with dimethylfulvene in ether or THF to yield exclusively lithium isopropenylcyclopentadienide, the product of proton transfer.Neither steric nor electronic effects alone appear sufficient to explain this anomalous result.A similar reaction in petroleum ether gives rise to three major products: lithium cyclopentadienide and the dilithium salts of 6-(1,3-cyclopentadienyl)-6,8,8-trimethylbicycloocta-1,3-diene and 2,4-bis(1,3-cyclopentadienyl)-4-methyl-1-pentene.The latter compound is a new dimethylfulvene dimer whose monoanion had previously been proposed but not observed as an intermediate in the anionic oligomerization of dimethylfulvene.
- Schore, N. E.,LaBelle, B. E.
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p. 2306 - 2310
(2007/10/02)
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