C-phenylation

Since the authors did not succeed in obtaining an ESR spectrum, they were unable to decide whether the IV-pyrazolyl radical is of the a (112a) or the v (112b) type. Ab initio calculations indicate that the radical has Bi (rr) symmetry (76T1555). However, the radical is formed from (111) as a cr radical and is able to react as such in its lifetime. This is in agreement with the experimental results (75JOC915), no C-phenylated pyrazoles being detected. 

With C-phenyl-/V-phenyl nitrones [10] (equation 7) Similar reactions of iV-methyl nitrone were also reported [70]. 

Such syn stereoselectivity also was observed for a number of additions of nitrones to fluoroallene, such as its reaction with N-phenyl-C-phenyl nitrone [25, 26, 27] (equation 19)... 

Heat gently 0 5 c.c. phenyl mustard oil, and o 5 c.c. aniline on cooling and rubbing with a gdass rod, thiocarbanilidc crystallises. 

Uiastereoselecdve catalydc nitro-aldol reacdons of opdcally acdve iV-phthaloyl-c-phenyl-alanal with nitromethanein the presence of LLB proceed with high diastereoselecdvityfruirdryii = 99 11 as shown in Eq. 3.76. The product is converted via the Nef teacdon into f3S,35 -3-amino-3-hydroxy-4-phenylbutanoic acid, which is a subunit of the HIV-protease inhibitor... 

R = H 3.5-Q-benzylidene-l-deoxy-2-C-phenyl-D-arabinitol yield 77% d.r. (39/40) 100 0 40 R = TBDMS 3,5-0-benzylidene-4-0-tert-butyldimethylsilvl-t-deoxy-2-C-phenyl-D-ribitol yield 89% d.r. (39/40) 0 100... 

FIGURE 15. The ( perpendicular ) torsional form of methyl-phenyl sulfone. The projection formula represents a view along the S—C(phenyl) bond. The other drawing shows the labels of the benzene ring angles. 

Deoxy-2-phenyl-a-D-glucopyranose or 2-deoxy-2-C-phenyl-a-D-glucopyranose or (2fl)-2-deoxy-2-phenyl-a-D-arab/no-hexopyranose... 

Porasil c Phenyl isocyanate Polar 60 C,-C5 hydro- u tens and their isomers. 

Phase Separation Spherisorb ODS1, ODS2, Cg, C phenyl, methyl, CN, NH2... 

C20H22O4 2(S)-4-0-Acetyl-3,5-0-benzylidene-l,2-dideoxy-2-C-phenyl- D-en/t/iro-pentitol ABYPEP 38 472... 

C20H24NOUPCH3OH 1,2,3,4-Tetra-O-acetyl-5,6-dideoxy-6-C-nitro-5-C-(phenyl-phosphinyl)-yS-L-idopyranose, methanolate IDPYRS 43 253... 

With base (e.g., pyridine) the reaction rate is enhanced. No thioamides could be obtained starting with ketonitrones. If C-phenyl-TV-methylnitrone is treated with thio-phosgene instead of a thioazolide, only N-methylbenzamide (73%) is formed, but no thioamide. 170 ... 

Presumably, 9 is actually formed from carbene 8 in the pyrolysis zone by a P/C phenyl shift, but then apparently succumbs to fast transformation into the thermodynamically stable final products. Formation of the methane derivative 13 should be preceded by a 1,2-phenyl shift to give the shortlived 10, the production of fluorene (14) by the occurrence of diphenylcarbene (II), and the formation of benzophenone (15) by isomerization to the angle-strained three-membered heterocycle 12, which is followed by elimination of phenylphospbinidene. No direct evidence is available for the intermediacy of 10-12. 

In the case of R = C6H5, the P/C phenyl shift dominates over the C/C shift to the extent of 2 1, the statistical factor already having been accounted for1U. 

Photolysis of the first known cyclic a-diazo-p-oxophosphine oxide 49 is unsuccessful with regard to phosphene formation. There is no evidence for a P/C-phenyl shift, which should lead to 51, nor for a P/C-alkyl shift, which would afford 52 via ring contraction, since none of the expected phosphinic esters could be isolated in methanolM). 

The Sm-N distances are consistent with single a bonds suggesting the presence of a (C H NNC.H dianion. However, the 1.25(1) a NN distance is the same" as tire N=N double bond distances in a variety of azobenzene structures. The molecule also contains distorted N-C (phenyl) distances, which are stretched from a normal 1.42 8 distance to 1.56-1.61 8. In addition, the samarium atoms are displaced asymmetrically such that both come within 2.29-2.34 8 of the ortho hydrogens of a single phenyl ring in a bonafide agostic (6<0 Sm-H interaction. The ability of Sm(II) to structurally distort azobenzene in this way is remarkable. 

The selective basic degradation of 1,2-dicarbaclovodode-carborane(12) and its C-methyl and C-phenyl derivatives has been recently reported.3 The ethanolic potassium hydroxide degradation of C, C"-dimethyl-l, 2-dicarbaclovododecaborane (12) and the isolation of the trimethylammonium salt of the resulting B9C2Hio(CH3)2 anion are described here as an illustration of this general reaction. The properties of the trimethylam-... 

Bis(oxazolinyl)pyridine-Ce(IV) triflate complex 78 catalyzed the enantioselective 1,3-DC of acyclic nitrones with a, 3-unsaturated 2-acyl imidazoles. For example, C-phenyl 7V-benzyl nitrone reacted with 77 in the presence of 78 to give the adduct 79 with excellent diastereo-and enantioselectivity. Isoxazolidine 79 was then converted into P -hydroxy-P-amino acid derivatives by hydrogenation of the N-0 bond in the presence of Pd(OH)2/C and cleavage of the 2-acyl imidazole with MeOTf in MeCN <06OL3351>. 

Many cycloadditions of nitrones86,172 174 and thiones give cycloaddition-cycloreversion equilibria. A-Methyl-C,C-diphenyl- and A-methyl-C-phenyl-nitrones, react with aliphatic thiones forming 1,4,2-oxathiazolidines, while 4 does not afford a cycloadduct.172 A-Methyl-C,C-2,2,4,4-tetramethyl-3-cyclo-butanonenitrone reacts with alicyclic thioketones to give 1,4,2-oxathiazolidines,174 while with 4 it enters into a metathesis reaction. 

Oxidation with Mn02 of N-glycosylhydroxylamines (48), obtained in the reaction of sugars (47), with A -methyl- and N -benzylhydroxylamines, leads selectively to the corresponding C -unsubstituted and C-phenyl-iV-glycosyl nitrones (49) (Scheme 2.18) (118, 119). 

The highly stereoselective 1,3-dipolar cycloaddition of C-phenyl-iV-glycosylnitrones (336) and (679) to dimethyl maleate D14, with the sugar moiety acting as a chiral auxiliary, has been used in enantioselective syntheses of isoxazolidines (678) and (678 ent) (Scheme 2.292) (118). 

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