Absolute configuration of (S)-(+)-3-ethyl-5-methyladamantane-1-carboxylic acid and (S)-(+)-1-amino-3-ethyl-5-methyladamantane

Abstract

The absolute configuration of (S)-( + )-3-ethyl-5-methyladamantane-1-carboxylic acid (Ia) and (S)-( + )-1-amino-3-ethyl-5-methyladamantane (!Ia) has been det~rmined by comparison of CD curves of the corresponding ( + )-N-methylthioamide I!d and salicylideneimino derivative lie with curves of the analogous derivatives of (S)-( + )-2-methylbutyric acid and (S)-( + )-2-aminobutane, resp. The absolute configuration has been proved by degradation of the (S)-( +)-acid !a to the amine Ila and comparison of CD curves of its salicylidene derivative lie.*** The molecule of adamantane represents a highly symmetric system ('ld symmetry).The appropriate substitution of this system may lead to compounds of two chirality types. Thus, by substitution at Cc 2 ) and Cc 6 ) carbon atoms a system is formed possessing the axial chirality; 2,6-dichloroadamantane-1,3,5,7-tetracarboxylic acid is the first substance of this type, prepared in the optically active form 1 . Appropriate SUbStitution at C(l)• C(3)• C(S)• and C(7) Carbon atoms Of the adamantane ring system results in substances of a central chirality, as shown for the first time by von Schleyer 2 • The first attempts in this respect to resolve the acids Ia, Ib, and Ic (Stepanov and Baklan 3 ) or to prepare the optically active acid Id (Malfer 4 ) were unsuccessful. Later on, the acid Id was resolved with the use of dehydroabietylamine (Me Kervey 5 ); the thus-obtained acid, though inactive at the D line, afforded by degradation the optically active 1-methyl-7-methylenebicyclo[3.3.1 Jnonan-3-one. When resolved with quinine 6 • 7 , the optical rotation of the acid Id at the D line was [a]~0 -0·36° (chloroform). In the recent time, ( + )-1-amino-3-ethyl-5-methyladamantane has been prepared 8 • In the present paper we wish to report determination of the absolute configuration Part XLVIII in the series Asymmetric Reactions; Part XLVII: This Journal38, 3299 (1973). Present address: Research Institute of Pharmacy and Biochemistry, Prague 9. All the adamantane derivatives prepared in the present work were inactive at the sodium D line but afforded monotonous positive ORD curves in the region of shorter wavelengths. On the basis of this effect, the absolute configuration is ascribed to these derivatives.

Directed C−H Bond Oxidation of Bridged Cycloalkanes Catalyzed by Palladium(II) Acetate

“…In 1964 Schleyer and co‐workers designed tri‐substituted adamantane derivative with central chirality and in 1974, Červinka and Hájíček achieved the first synthesis of optically pure adamantane derivative of such type . To the best of our knowledge, we herein describe the first synthesis of a 2,8,9‐tri‐substituted chiral adamantane derivative with C 3 ‐symmetry.This molecule was proposed in the work focused on the synthesis of the smallest organic triol with C 3 ‐symmetry by Haufe group .…”

The salicylidenamino chirality rule: a method for the establishment of the absolute configurations of chiral primary amines by circular dichroism

“…In the XH NMR spectra of the IV-salicylidene derivative of the (S)-1-alkyl-2-propenylamines [(S)-25a-c], the methine proton of the SA group appears as a singlet,31 indicating a preferred conformation (27) such that the hydrogen atom at the chiral center is eclipsed by both the carbon-nitrogen (27a) and carbon-carbon double bonds (27b). 69 For the configuration shown in each conformer, the sign, as shown, of its contribution to the sign of the observed CEs of bands I and II is determined by the chirality of the attachment bonds of the SA and phenyl groups.…”