2- -2-phenylethyl

Imine of compound 2 2-Butanone. 4-[1-methyl-2-[(1-phenylethyl)iminolcyctohexyl]-,... 

P-Phenylethylamine. Prepare p-phenylethyl phthalimide as above by substituting P phenylethyl bromide (Section 111,37) for benzyl... 

Hydrocinnaniic acid Aliphatic acid -Phenylethyl alkyl ketone... 

Ethyl p-phenylethyl ketone. Use 100 g. of pure hydrocinnamic acid and 200 g. (201 -5 ml.) of pure propionic acid. Fractionation of the distillate yields 70 g. of diethyl ketone (b.p. 100-102°), 72 g. of ethyl p-phenyl-ethyl ketone (b.p. 245-249° the pure ketone boils at 248°), and 18 g, of crude di-p-phenylethyl ketone (high b.p. residue). 

Styrene may be conveniently prepared in the laboratory by heating p-phenylethyl alcohol (Section IV,204) with sohd sodium or potassium hydroxide when an almost quantitative dehydration occurs ... 

In a 250 ml. distilling flask (1) place 122 g. (119 ml.) of p-phenylethyl alcohol and 40 g. of sodium hydroxide peUets (or 56 g. of potassium hydroxide). Heat is evolved. Warm gently until bubbles commence to form and the mixture separates into two sharply-defined layers. Distil slowly water, etc. passes over first accompamed by the gradual dis appearance of the upper phase. FinaUy the styrene passes over at 140 160° (mainly 150°) coUect this separately in a receiver containing about 0 1 g. of hydroquinone. Dry the distillate with a httle anhydrous calcium chloride or magnesium sulphate, and then distil under reduced pressure (2). C oUect the pure styrene at 42-43°/18 mm. The 3rield is 80 g. Add about 0-2 g. of hydroquinone (anti-oxidant) if it is desired to keep the phenylethylene. 

In cases of more effective 7t-electron donor or tz-donor neighboring groups, as is the case in forming /3-phenylethyl (studied by Don Cram from UCLA Nobel Prize in chemistry, 1987) or /3-halogen bridged species, these have sufficient electrons to form 2e-2c bonds (with some intermediate delocalization). 

Progress has been made toward enantioselective and highly regioselective Michael type alkylations of 2-cyclohexen-l -one using alkylcuprates with chiral auxiliary ligands, e. g., anions of either enantiomer of N-[2-(dimethylamino)ethyl]ephedrine (E. J. Corey, 1986), of (S)-2-(methoxymethyl)pyrrolidine (from L-proline R. K. EHeter, 1987) or of chiramt (= (R,R)-N-(l-phenylethyl)-7-[(l-phenylethyl)iinino]-l,3,5-cycloheptatrien-l-amine, a chiral aminotro-ponimine G. M. Villacorta, 1988). Enantioselectivities of up to 95% have been reported. 

None of the bonds to the chirality center is broken when hydroxide attacks the carbonyl group Had an 8 2 reaction occurred instead inversion of configuration at the chirality center would have taken place to give (8) (—) 1 phenylethyl alcohol... 

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