Some 9-membered heterocyclic rings incorporating the 8- and 8' positrons of 1,1'-binaphthyl

Abstract

Four, new nine-membered ring compounds, 8,9-dihydro-7H-cyclonona{1,2,3-de: 4,5,6-d'e'}-dinaphthalenes with heteroatoms in the 8 positions, have been prepared, where the heterofunction is -O- (I), -S-(II) ,-Se-(III) and -SO ₂-(IV), in the racemic and optically active states [diagram].

The oxygen-bridged compound (I) was made from 8,8'-bishydroxymethy1-1,1'-binaphthyl while the sulphur (II) and selenium (III) compounds were synthesised from 8,8'-bisbromo-methyl-1,1'-binaphthyl; the cyclic sulphone (IV) was prepared by oxidation of the sulphide (II).

The following nine-membered ring heterocyclic and carbo-cyclic analogues, which had been described previously but were not available in sufficient quantity for further study were also synthesised. 8,8'-Biscyanomethy1-1,1'-binaphthyl [diagram](XIX) was also prepared for further investigation.

The optically active heterocyclic bridged compounds were synthesised from optically active precursors derived from resolved 1,1'-binaphthyl-8,8'-dicarboxylic acid (XV); the carbocyclic ones were prepared from the bridged di-acid (IX), resolved through its quinidine salt.

The absolute configurations of all these compounds are unequivocally assigned through synthetic routes which link them with (+)-2,2'-dihydroxy-1,1'-binaphthyl-3,3'-dicarboxylic acid dimethyl ester established as of (R)-configuration by the x-ray crystallographic method by Akimoto and his coworkers (1971). Thus we find that the new compounds (+)I, (+)II, (+)III, and (+)IV have the (S)configuration; (+)V, (+)VI, (+)VII, (+)VIII, (+)IX, (+)X, (+)XI, (+)XII, (+)XIII, and (+)XIV also have the (S), while (+)XV and its methyl ester (+)XVI have the (R) configuration.

The proton nuclear magnetic resonance spectra of all the bridged compounds show the pairs of diastereotopic geminal methylene protons of the 9-ring to be spin-spin non-equivalent and to have large coupling constants. Shift reagents have assisted in the assignment of signals.

The corresponding geminal methylene protons of 8,8'-dihydroxymethyl-1,1'-binaphthyl, previously found to give a single signal, have been shown as diastereotopic in deutero-dimethyl sulphoxide and studied at varying temperature. The ultraviolet spectra show the general characteristics of the spectrum of 1,1'-binaphthyl itself. In the series -O-, -SO₂-, -S-, -Se-, there is a small progressive red shift in the maximum of the short wave band and of a shoulder on the long wave side of it. This band is followed by a minimum; minima show red shifts in the same order as the maxima, and at the same time become progressively shallower troughs; the minimum for the -O- compound is similar to that of unbridged compounds.

Optical rotatory dispersion and circular dichroism spectra were obtained for the four new compounds (I), (II), (III), (IV), and for the unbridged compound (XIX). The range of wavelength was extended for the previously recorded o.r.d. and c.d. spectra of (V)-(XVIII). Particular attention is paid to the short wave couplet and to the longer wavelength features shown by each compound, and comparisons are drawn between the c.d. spectra of the different types of structure. All the compounds of (S) configuration, except for the 8,8'-bridged ones, have a negative c.d. band in the 285-315 region: in contrast, the (S)-8,8'-bridged compounds show c.d. of opposite sign in this region.