Face selection in the reduction of p,p'-disubstituted 5,7-diphenyl-2-adamantanones and hydrolysis of the corresponding 2-adamantyl tosylates

• Published in: Journal of organic chemistry Vol. 59; no. 1; pp. 58 - 66
• Main Authors: Song, In H, le Noble, William J
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.01.1994; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Exact sciences and technology; Kinetics and mechanisms; Organic chemistry; Physical Sciences; Reactivity and mechanisms; Science & Technology; SUBSTITUTION; SYSTEMS; NUCLEOPHILIC-ADDITION; DIASTEREOSELECTIVITY; PARTICIPATION; Substituent effect; Chemical reduction; Arrhenius equation; Solvolysis; NMR spectrometry; Kinetic parameter; Tricyclic compound; Rate constant; Experimental study
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo00080a012

The reduction of 5,7-diphenyl-2-adamantanone with sodium borohydride in 2-propanol is affected by the introduction of a p-nitro substituent in one of the rings: the E-alcohol is obtained in small but easily measurable excess of 1.30:1. Conversely, the introduction of a p-amino group leads to an excess of Z-isomer by roughly the same factor (1.28). When both substituents are present, they evidently cooperate to produce a ratio of 1.64. The tosylates of the alcohols were prepared and their solvolysis rates measured in 3% aqueous hexafluoro-2-propanol and compared with those of the parent and p-substituted 5-phenyl-2-adamantyl tosylates. Additivity of substituent effects was again observed, but the p-aminophenyl group in these reactions was deactivating compared to phenyl, presumably due to II-bonding and/or protonation of the amino group in the acidic medium.