Tri-phenyl Methyl

Als Kondensationsmittel besonders geeignet erwies sich das Tri-phenyl-methyl-Kalium, da es im Gegensatz zum Na-Salz in kochendem Ather bestandig ist (60). 

The very first radical to be detected, the tri phenyl methyl radical, was made in 1900 by abstraction of Cf from PhaCCI byAg metal. 

This radical is relatively stable (we shaii see why shortly), but reacts with itself reversibly in solution. The product of the dimerization of tri phenyl methyl was for 70 years believed to be tetra phenyl ethane but, in 1970, NMR showed that it was, in fact, an unsymmetrical dimer. 

The quinonoid theory, however, was not entirely satisfactory because, for example, di-iminoquinone is colourless. An interesting observation was made by Gomberg in 1899 when he demonstrated the existence of tri-phenyl methyl, which is a yellow colour. This radical contained one trivalent carbon atom, and isolated unsaturated atoms were added to the list of chromophores. 

This mode of dimerization is analogous to that operating in the dimerization of the sterically hindered tri-phenyl-methyl radicals101). 

Methyl Acrylate CH2=CHCOOCH3 Non-inhibitors such as Biphenyl, Bibenzyl, Tri-phenyl, etc Methyl Acrylate Vap plus air > Ambient > 120 Inhibitor—H ydro quino ne or Methyl Ether of Hydro-quinone 10-20ppm. Store Store below 10° no inert atmosphere. No sparks 18.58-18.8 463 Self polymerizing above ambient press temp accelerates polymerization... 

Trihydroxy-2,3,5-tris-[4 -methyl-phenyl]-1-(4-methyl-bcnzoyl)- 658... 

A. Preparation.—The first reverse Wittig olefin synthesis has been reported. Triphenylphosphine oxide and dicyanoacetylene at 160 °C gave the stable ylide (1 78%) the reaction was reversed at 300 °C. No comparable reaction was observed with a variety of other activated acetylenes but tri phenyl arsine oxide gave the corresponding stable arsoranes with dicyanoacetylene (— 70 °C), methyl propiolate, hexafluorobut-2-yne, dimethyl acetylene dicarboxylate, and ethyl phenylpropiolate (130 °C). 

The first examples of mononuclear disulfur and diselenium complexes of platinum have been described.330 Reduction of the sterically hindered complex trans- PtC 2( P M e2A r)2] (Ar = 2,4, 6-tris[bis(trimethylsilyl)methyl]phenyl, 2,6-bis[bis(trimethylsilyl)-methyl]-4-[tris(trimethylsilyl) methyl]-phenyl) with lithium naphthalide in THF solution affords the platinum(0) species [Pt(PMe2Ar)2]. Oxidative addition of elemental sulfur or selenium yields the dichalcogenatoplatinum(II) complexes of the type [PtE2(PMe2Ar)2] (E = S, Se) containing a unique PtE2 ring system. The complexes are stable to air in the solid state, but slowly decompose in solution after several days at room temperature. 

The reaction of 2-deoxy-3,4,6-tri-0-methyl-2-methylamino-D-glucopyranose 149 with methyl(phenyl)phosphonic dichlorides (106a-b) or methylthiophosphonic dichloride in benzene in the presence of triethylamine afforded mixtures of four isomers of the corresponding 1,3,2 oxazaphospholidine-2-ones 150, 151 and... 

Actually, 64 is known to be dimeric in the solid state but monomeric in dilute solution or in the gas phase. The first monomeric dialkyl- and diarylstannylenes are 2-pyridylbis[(tri-methylsilyl)methyl]-substituted stannylenes and bis[2,4,6-tris(tiifluoromethyl)phenyl]stan-nylene it should be stressed, however, that the coordination number around Sn in the solid state is not 2 in these compounds. The first actual monomer with coordination number 2 in the solid state was found to be 2,2,5,5-tetrakis(trimethylsilyl)cyclopentane-l-stannylene, 65, prepared by the following reaction141 ... 

Auch kern-substituierte Phenylierungs-Reagenzien konnen verwendet werden. So erhalt man z.B. aus Anilin mit Diacetoxy-tris-[4-methyl-phenyl]-bismut (4-Methyl-phenyl)-phe-nyl-amin in 98% Ausbeute1. 

Oxazolidine konnen reduktiv zu 3-Amino-alkanolen gespalten werden, wie die Re-duktion von 2-Methyl-3-phenyl-5-(trimethylsilyl-methyl)- und 2-Phenyl-3-propyl-5-(tri-methylsilyl-methyl)-l, 2-oxazolidin zu 2-Hydroxy-4-metkylamino-4-phenyl-l-trimethylsi-lyl-butan bzw. 4-Anilmo-2-hydroxy-l-trimethylsilyl-heptan zeigt die so erhaltenen Amino-... 

Analog reagiert Brom-ethen mit 3,3-Dimethoxy-propen und Piperidin bei 100° (20 h) in Gegenwart von Palladium-acetat und Tris-[2-methyl-phenyl]-phosphan zu 5,5-Dimethoxy-1 -piperidim-2-penten (57%)2. 

Meanwhile, Tokitoh et al. " reported the first example of thermal dissociation of extremely hindered disilenes [Tbt(Mes)Si=Si(Mes)Tbt Tbt = 2,4,6-tris[bis(tri-methylsilyl)methyl]phenyl, Mes = 2,4,6-trimethylphenyl (mesityl) fZ)-137 cis isomer, (E)-137 trans isomer] into the corresponding silylene [Tbt(Mes)Si , 138] under very mild conditions (—70 °C) as shown in Scheme 14.59. 

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