Stereochemistry of displacement reactions at the neopentyl carbon. Further observations on the triphenylphosphine-polyhalomethane-alcohol reaction

Abstract

27124-75-0 77.03 8.31 77.17 8.29 methoxyphenyl) cy clohexanemercaptoacetic acid, 27124-87-4; ci's-2-(3' ,4 '-dimethoxyphenyl) cy clohexanemercaptoacetic acid, 27124-88-5; cís-2-(2',5'-dimethoxyphenyl) cy clohexanemercaptoacetic acid, 27124-89-6; cis-2 -(2',3' -dimethoxyphenyl) cy clohexanemercaptoacetic acid, 27124-90-9; 1-(2',5'-dimethoxyphenyl)cyclohexene, 1848-14-2; 1-(2', 6 '-dimethoxyphenyl) cyclohexene, 27124 -92 -1; 1 -(2',4' -dimethoxyphenyl)cyclohexene, 27098 -25-5; 1 -(3',4' -dimethoxyphenyl)cyclohexene, 27124-93-2; frans-2-(2',4'-dimethoxyphenyl)cyclohexanemercaptoacetic acid,13 27124-94-3; frans-2-(3',4.'dimethoxyphenyl) cyclohexanemercaptoacetic acid,1327124-95-4;trans-2-(2 '-methoxyphenyl) cyclohexanemercaptoacetic acid,13 27124-96-5.

Synthesis of (+/−) arthrographol

“…Crystallization of the mixture of dienes containing mainly the (E,E) isomer gave the pure (E,E)-diene whose 'H nmr spectrum was identical with that of dimethylarthrographol prepared by methylation of natural (-) arthrographol. Hydrogenation of the mixture of dienes obtained from the Wittig reaction gave tetrahydrodimethylarthrographol (13), which was identical ('H nmr) with the product of methylation and hydrogenation of natural (-) arthrographol…”

“…The iodide 15 and chloride 17 were prepared in high yield from reaction of the alcohol 6 with iodine-imidazole-triphenylphosphine in benzene (1 1) and a~etonitrile,~ and N-chlorosuccinimide-triphenylphosphine in tetrahydrofuran (THF) (12), respectively. Attempts to form the bromide 16 with either N-bromosuccinimide-triphenylphosphine in THF or carbon tetrabromide -triphenylphosphine in THF or dichloromethane (13) Attempts to convert the iodide 15 into the resorcinol 18 with boron tribromide in dichloromethane led to decomposition, while the bromide 16 gave a low yield of the corresponding resorcinol 1 9 but this material was contaminated with considerable amounts of dibromo impurities (hreims, cims). Finally, cleavage of the methyl ether of the chloride 17 was investigated and it was found that reaction with 2 equivalents of boron tribromide in dichloromethane at room temperature gave nearly quantitative yields of the resorcinol20.…”

Photocatalyic Appel reaction enabled by copper-based complexes in continuous flow

“…One such process is the Appel reaction [ 5 ], which employs PPh 3 and an electrophilic halogen source to promote the formation of an organic halide from the corresponding alcohol ( Fig. 1 ) [ 6 – 7 ]. The Appel reaction is representative of a host of transformations that require stoichiometric reagents to effect a functional group change of an alcohol.…”

A New Facile Route to Chlorination of Alcohols via Lewis Acid AlCl<sub>3</sub>

“…The most recent development can be linked to the discovery that the cooperation of InCl 3 and HSiMe 2 Cl enable chlorodehydroxylation of alcohols into organic chlorides in the presence of benzyl [5]. The other methods utilize Ph 3 P-CCl 4 [6][7][8], PCl 5 [9], thionyl chloride [10], phenylmethyleniminium [10], benzoxazolium [11], Vilsmeier-Haack [12], and Viehe salts [13] as chlorination reagents, among them, HCl involved chlorination process represents the most prominent example of this reaction class [14][15][16][17][18]. Despite intensive research efforts over the past few years, the conversion usually requires elaborate reagents and quite drastic reaction conditions.…”