Phenylmagnesium bromide 2.6- dichloro

R)- and (,S )-1.1,2-Triphenyl-l,2-ethancdiol which are reliable and useful chiral auxiliary groups (see Section 1.3.4.2.2.3.) also perform ami-sclcctive aldol additions with remarkable induced stereoselectivity72. The (/7)-diastercomer, readily available from (7 )-methyl mandelate (2-hy-droxy-2-phcnylaeetate) and phenylmagnesium bromide in a 71 % yield, is esterified to give the chiral propanoate which is converted into the O-silyl protected ester by deprotonation, silylation, and subsequent hydrolysis. When the protected ester is deprotonated with lithium cyclohexyliso-propylamide, transmetalated by the addition of dichloro(dicyclopentadienyl)zirconium, and finally reacted with aldehydes, predominantly twm -diastereomers 15 result. For different aldehydes, the ratio of 15 to the total amount of the syn-diastereomers is between 88 12 and 98 2 while the chemical yields are 71 -90%. Furthermore, high induced stereoselectivity is obtained the diastereomeric ratios of ami-15/anti-16 arc between 95 5 and >98 2. 

Summary Two series of 2-furyl-, 2-(4,5-dihydrofuryl)-, 2-thienyl-, and phenyl-silacyclopentanes and sllacyclohexanes have been synthesized by the reactions of 1,1-dlchloro-l-sllacyclopentane and 1,1-dichloro-l-silacyclohexane with corresponding hetaryl lithium or phenylmagnesium bromide. The influence of the heterocycle and the nature of the silacycloalkane on the chemical shifts in the H, C and Si NMR spectra has been investigated. NMR data indicate a complex character of the mutual influence of heterocyclic substituents on shielding of the nuclei. 

The reaction of 3,5-dichloro-A,A-diisopropyl-1 /.4,2,4,6-thiatriazin-l -amine (2) with butyllithi-um gives only dibutyl ketone, probably formed from the ring-transformation product benzoni-trile via butyllithium addition to the ketone imine.45 Reaction of phenylmagnesium bromide with 2 gives 3-chloro-Al,Af-diisopropyl-5-phenyl-lA4,2,4,6-thiatriazin-l-amine (3) in 30% yield.45... 

Procedure [149]. Dihydropyran (DHP)-resin 4a (6.0 g) in dichloro-ethane (70 mL) was treated with A-etiioxycarbonyl-rran5-4-hydroxy-L-pro-line methyl ester (21 mmol) and PPTS (6.7 mmol) and the suspension heated to 80°C for 48 h, filtered, washed with CH2CI2 (8 X 50 mL), and dried. The resin-bound methyl ester (1.0 g, 0.43 mmol) in tetrahydrofuran (THF) (25 mL) was treated with phenylmagnesium bromide in THF (50 equiv.) at 0 C and the mixture allowed to warm to ambient temperature and stirred for 12... 

Step conversion. A slight excess of ethereal phenylmagnesium bromide added to a soln. of 3,4-dichloro-6-methylcoumarin in benzene 3-chloro-6-methyl-flavone. Y 70%. M. S. Newman and J. L. Ferrari, Tetrah. Let. 1962, 199. 

Zinc(II) chloride-tetramethylethylenediamine complex (4.23 g, 16.7 mmol), 1,10-phenanthroline (101 mg, 0.56 mmol), and benzo[/t]quinoline (1.00 g, 5.6 mmol) are placed in a Schlenk tube. To this mixture a solution of phenylmagnesium bromide (33.5 mL, 1.00 M, 33.5 mmol) in tetrahydrofuran is added dropwise at 0 °C. After stirring for I h, a 0.1-M solution of tris(acetylacetonato)iron in tetrahydrofuran (5.6 mL, 0.56 mmol) and 1,2-dichloro-2-methylpropane (1.42 g, 11.2 mmol) are sequentially added. The reaction mixture is stirred at 0 °C for 16 h and is quenched by the addition of a saturated aqueous solution of sodium bicarbonate (40 mL). After extraction with ethyl acetate (25 mL, 3 times), the organic layer is dried over sodium sulfate and concentrated under reduced pressure. The crude product is purified by silica gel chromatography (eluent first hexane to elute the biphenyl, then toluene) to afford 10-phenylbenzo[A]quinoline as a colorless solid mp 90.6-92.5 1.39 g (98%). ... 

---