Reduction of glutinone (alnusenone) (V) with aluminium isopropoxide and isopropanol gives a mixture of glutin-5(6)-en-3a-(VII; R = H) and -3P-01 (IV; R = H). Reduction of glutin-5(10)-en-3-one (VIII) with lithium aluminium hydride gives a mixture of the epimeric alcohols glutin-5( 10)-en-3P-(X; R = H) and -361-01 (XI; R = H). The configuration of the hydroxyl group in glutin-5(10)-en-3a-ol (XI; R = H) was established by oxidation of its acetate to glutina-l(l0) : 5-dien-3a-yl acetate (XIII; R = Ac), previously obtained by similar oxidation of glutin-5(6)-en-3a-yl acetate (VII; R = Ac). Likewise, the configurations of the hydroxyl group in glutin-5(10)-(X; R = H) and -5(6)-en-3@-01 (VI; R = H) were confirmed by the oxidation of the acetates to glutina-l(l0) : 6-dien-3fl-yl acetate (XII; R = Ac).In Part LIV of this series, the constitution and stereochemistry of glutinone (alnusenone) (V) were deduced and were confirmed by partial synthesis from the saturated ketone, friedelin (VI).1 The biogenesis of friedelin from a squalene-like precursor is considered to proceed via the carbonium ion (I) which is also the immediate precursor of P-amyrin (11). Rearrangement of the carbonium ion by a synchronous series or by a succession of 1 : 2shifts of the axial methyl groups or the axial hydrogen atoms attached at positions 14, 8, 9, 10, 5, and 4, and loss of the hydrogen attached at position 3 as a proton, leads to friedelin 3 (VI). Taraxerol (111) considered to be a stabilised intermediate in this biogenetic route. The biogenesis of glutinone from the carbonium ion (I) is represented as a series of 1 : 2-shifts of the axial methyl groups or axial hydrogen atoms attached at positions 14, 8,9, 10, and 5 and loss of a proton from C (6). This route, which is illustrated by the arrows in (I), would lead to glutin-5(6)-en-3p-ol (IV; R = H), and the depicted changes are either followed or accompanied by oxidation of the secondary alcohol group. The possible intermediate glutin-5(6)-en-3(3-01 (IV; R = H) , in which the hydroxyl group is axial, has so far not been isolated from a natural source, but it has now been prepared from glutinone. Reduction of glutinone (V) with lithium aluminium hydride 53 6 or with sodium and alcohol gives an alcohol (m. p. 203-205", [a]= +61"; acetate, m. p. 235-236", [a]D +46") in which the hydroxyl group is equatorial and consequently a-orientated. Oxidation of the alcohol regenerates glutinone and it is therefore identified as glutin-5(6)en-3a-011 (VII; R = H). We now find that reduction of glutinone (V) with aluminium
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.