Twistan-4-one

Turmerone, T16 Tutin, T31 Twistane, XIO Twistan-4-one, XIO Twistene, XIO Tylosin, Y25 Tyrosine, A5 Tyrosinol, A5... 

Twistane derivatives (tricyclo [4.4.0.03>8 ] decanes) may be prepared in one step from the readily available ds-decal in-2,7-dione (Eq. (26)) 85, 86. ... 

In the series of dihetero-tricyclodecanes, substitutions and rearrangements involving neighboring group participation of heteroatoms (onium ions) especially of oxygen (oxonium ions) sulfur (episulfonium ions, thiiranium ions) and nitrogen (ammonium ions, aziridinium ions) as well as in one case also of selenium (epi-selenium ions), were studied on adamantanes (G1), isotwistanes (G 2), twistanes (G 2) and homotwistbrendanes (G 4). 

Analogously to the isotwistanes (see 3.2.3.) twistanes with only one leaving group R -C(10) (R = H, type G 45) were subjects for studies of neighboring group participation. The results are listed in Table 4. 

One of the most suitable starting materials for the preparation of further derivatives of 2-aza-7-thia-twistanes is the 10 -bromide 234 (2.3.4.). Oxidation with one equivalent of hydrogen peroxide gave a mixture of the two sulfoxides 238 (19%) and 372 (38%). The former was identical with the one obtained by cyclization of the bicyclic compound 237 (2.3.4.). This allows conclusive assignment of the orientation of the oxygen atoms in the two sulfoxides 238 and 372. 

The subsequently applied synthetic scheme was analogous to the one for the corresponding racemic compounds (see 2.2.2.I., 3.2.3. and 3.2.4.). Treatment of the (—)-alcohol 379 with iodine in chloroform yielded the (-)-10° -iodide 383 as sole product. Its reaction with silver tosylate in acetonitrile led to a mixture of 10°(7).tosyloxy-isotwistane 384 and -twistane 386, which was directly treated with LiAlH4 in refluxing dioxane to give a mixture, easily separable by vpc., of (—)-2,7-dioxa-isotwistane 385 [oc]d = —23.3 0.7°) and (-)-2,7-dioxa-twistane 387, see Table 8). The absolute configuration of 387 [(—)-( R, 3R, 6R, 8R), right-handed helix (P)] and of all other compounds involved in its synthesis was determined by chemical correlation with (—)-(2S)-malic acid (559). As relais compounds served the endo-2-hydroxy-9-oxabicyclo[3.3.1]nonanes +)-390 and (—)-J97, (-t)-5-hydroxy-cyclooct-l-ene [ +)-392] and the 4-methoxy-suberic acid dimethylester —) 393 and +)-394. 

On the basis of chemical correlations Tichy was able to deduce the absolute configuration of carbocyclic (+)-twistane (403) as (IR, 3R, 6R, 8R), left-handed helix (M). Comparison of this result with the ones described in 4.6.1. and 4.6.2. demonstrate, that carbocyclic twistane and 2,7-dioxa-twistane having the same sign of the optical rotation, possess the same helicity (see Table 8). 

For tricyclo[4.3.1.0 ]decane the following trivial names were introduced in the literature isoadamantane (1968) protoadamantane (1968) isotwistane (1969) and 2(3 - 4)abeo-adamantane (1970) In the present review the name isotwistane will be applied, which until now is exclusively used to describe such 2,7-dihetero-tricyclodecanes. However, one should pay attention to the fact that since 1972 the trivial name iso-twistane is also applied for tricyclo[4.3.1.0 )decanes. 

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