Whereas previously aromatic SrnI reactions were conducted almost exclusively in ammonia, it is now found that dimethyl sulfoxide is a good solvent for photostimulated reactions of diethyl phosphite ion, thiophenoxide ion, and acetone enolate ion with iodobenzene. Yields in the iodobenzene-diethyl phosphite ion reaction were also high in acetonitrile and dimethylformamide and fairly good in tert-butyl alcohol, but poor in hexamethylphosphoric triamide and some other common dipolar, aprotic solvents. In tert-butylamine, attempted reactions with thiophenoxide and acetone enolate ions were not very satisfactory, but iodobenzene as well as m -bromoiodobenzene underwent rapid photostimulated reaction with diethyl phosphite ion. In water, poor yields were obtained in photostimulated reactions of thiophenoxide ion with two substrates which were the more reactive of several tried.

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cis coupling constant being 6-7 Hz and the trans coupling constant 12-14 Hz.26 The configurations of the geometric isomers of 9 were assigned as follows. The first step in the synthesis of 9 involves a reaction between the dimethyl acetal of methyl isobutyl ketone and 2-bromoethanol under acid conditions, which leads to a formation of the isomeric species ¿-BuC(OCH2CH2Br)=CH2 and (£)and (Z)-MeC(OCH2CH2Br)=CHPr-i. From previous thermodynamic studies12,17,19 it can be inferred that the more stable geometric isomer has the E configuration. In the second step, HBr is eliminated from the product of the first stage, and since this process is carried out under basic conditions, no (significant) isomerization occurs during this step. Hence the predominating geometric isomer of the final synthetic mixture must have the E configuration. The same arguments were applied for the identification of the geometric isomers of 10.Determination of Normal Boiling Points. The standard enthalpies and entropies of vaporization at 298.15 K were estimated from the values of the normal boiling points of the compounds studied. The boiling points were determined by the gas chromatographic method described previously.12 The values obtained follow (in °C):

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