2,4,6-Trimethylphenylation

Dihydroxotris(2,4,6-trimethylphenyl)antiQomy [113002-54-3] C2yH2502Sb, is the only compound of this class, the stmcture of which has been confirmed by x-ray diffraction (163). 

Thieno[2,3-d]isoxazoline, 4,4-dioxo-3-(2,4,6-trimethylphenyl)-3 a,6a-dihydro-synthesis, 6, 998... 

A variety of silver(I) carbenes can be prepared by interaction of a series of imidazolium salts with silver(I) oxide or silver(I) carbonate (OOJCS(D) 4499). With 3-tert-butyl-l-(2 -pyridylmethyl)imidazolium bromide hydrate and 3-(2", 6"-di-Ao-propylphenyl)-l-(2 -pyridylmethyl)imidazolium bromide hydrate, complexes 85 (R = t-Bu, 2",6"-/-Pr2CgH3) result. 3-(2",4",6"-Trimethylphenyl)-l-(2 -pyridylmethyl)imidazolium bromide in turn leads to 86 (R= 2",4",6"-MejCgH2). 3-(2",6"-Di-wo-propylphenyl)-l-(2 -pyridyl)... 

Fluorinated 1,2-diazepines (23) can be prepared by the thermolysis of 2,4,6-trimethylphenyl azo compounds with elimination of HF from the Me and F ortho to the azo linkage [84CC832 88JFC(41)439]. The oxidation of these unsymmetrical diareno-1,2-diazepines gave N-oxides and diazepi-nones, depending on the oxidant [89JCS(P1)1117]. 

Second-generation ruthenium-carbene complex, (tricyclohexylphosphine-[l,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene]ruthenium (IV) dichloride),4e was purchased from Strem Chemicals. 

Tricyclohexylphosphine[l,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene]ruthenium... 

Cp pentamethylcyclopentadienyl Tmp 2,2,6,6-tetramethylpiperidine Dipp 2,6-di(iso-propyl)phenyl Trip 2,4,6-tri(iso-propyl)phenyl Mes 2,4,6-trimethylphenyl Mes 2,4,6-tri(tert-butyl)phenyl Ada adamantyl dmap 4-(dimethylamino)pyridine Tms trimethylsilyl (SiMe3)... 

The versatile starting material lCp RuCI 4 (1) reacts rapidly with sterically demanding phosphines (PCy and P Pr ) as well as with the nucleophilic carbene ligands (L) to give deep blue, coordinatively unsaturated Cp Ru(L)CI complexes 2-8 (L= l,.Tbis(2,4,6-lrimethylphenyl) (IMes. 2) 1,3-R2-imidazol-2-ylidene = cyclohcxyl (ICy, 3) 4-methylphenyl (ITol, 4) 4-chlorophenyl (IPCl, 5) adamanlyl (lAd, 6) 4..5-dichloro-1,3-bis(2.4,6-trimethylphenyl) (IMesCI, 7) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidenc (IPr. 8) in high yields according to Eq. (4). 

Fig. 10.6. Dimeric (Ar = 2,6-dimethylphenyl) (a) and monomeric (Ar = 2,4,6-trimethylphenyl) (b) copper complexes with diphenylcarbene. Reproduced from J. Am. Chem. Soc., 126, 10085 (2004), by permission of the American Chemical Society.

The following abre viations are used for the substituents. Ad = 1 -adamanty 1 Dep = silyl)methyl Dmt = 4-t-butyl-2,6-dimethylphenyl Mes = 2,4,6-trimethylphenyl Tbt phenyl Xyl = 2,6-dimethylphenyl. b By UV irradiation of the E-isomers. c Mixture of - and Z-isomers. d Presumed Z. 

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