260 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS intermediate, as portrayed below. A similar 1,4- hydroboronation occurs with a- gurjunene (30). HO•' _-- The identity of (--)-cis-m-menth-4-en-8-ol (formula 31) was confirmed by its preparation from (+)-cis-caran-cis-5-ol (formula 26), by pyrolysis (11, 31) and by reaction with 0.1N hydrochloric acid (8). The acid cata- lysed reaction takes place as shown below. H, x f U + ioo % 50 (24) (11) (32, t{, [•-, ct- CH2OH) (31) 20 50 I10 150 170 Temperature, øC Figure 3. Approximate compositions of the alcohol mixtures from the oxidafire hydro- boronarian of (+)-car-3-ene (formula 2) at different temperatures.

SOME INVESTIGATIONS OF THE CHEMISTRY OF CARENE 261 IOO % 5o (24) (17) (11) 0 I0 20 30 40 50 Time, rain Fig•r• 4. Percentage of alcohols (formulae 11, 17, 24 and 31) formed as a function of time at 100 ø. [(formula 11) (--)-cis-caran-lrans-2-ol, (formula 17) (--)-cis-caran-trans-4-ol, (formula 24), (--)-cis-caran-trans-5-ol, (formula 31) (--)-cis-m-menth-4-en-8-ol] The cis- and trans-caran-10-ols (formula 32, R, [1-, a-CH2OH) were not separable by glc nor through their 3,5-dinitrobenzoates, nor was there any evidence from the nmr spectrum of their mixture that more than one component was present. This spectrum showed a multipier at t 9.2-9.6 (cyclopropane protons), singlets at • 9.04 and 9.6 (gem-dimethyl groups), a doublet at ß 6.70 (J 5.SHz CH2-10), and a singlet at • 6.6 (OH) removed by deuteriation. We were not surprised by the difficulties in separ- ation of these 10-ols, for earlier (12)we had shown that the closely related hydrocarbons, (--)-cis- (formula 5) and (q-)-trans-carane (formula 6) were in- separable by glc since they are quasi-enantiomeric. Nevertheless, these hydrocarbons showed small, but quite distinct differences in their ir and nmr spectra (12). We made use of these facts in assessing the com- position of the mixture of the 10-ols. Thus reduction of their mixed toluene p- sulphonates with lithium aluminium hydride gave a mixture of equal quantities of cis- (formula 5) and trans-carane (formula 6). The formation of