The precursor for (-)-a-multistriatin (alkyl 2,3,4-trideoxy-2,4-di-C-methyl-a-D-Zyxo-hexopyranoside) may be approached from the corresponding isomeric 4-oxo-2-C-methyl-or 2-oxo-4-C-methylpyranosides by (a) methylenation followed by (b) hydrogenation. The yields in step a and stereocontrol in step b have been found to depend strongly on a number of factors including the protecting group for the C6 hydroxyl. For elaboration to the multistriatin skeleton, the glycosidic methoxyl is hydrolyzed under neutral conditions by using refluxing dimethoxyethane-water which avoids any epimerization of the C2 methyl group. The resulting glycose is treated with vinylmagnesium bromide, and the allylic alcohol obtained is oxidized with manganese dioxide. Exposure of the enone to hydrogen then leads directly to a-multistriatin.«-Multistriatin, a component of the aggregation pheromone of the elm bark beetle Scolytus multistriatis, was isolated, characterized, and synthesized in racemic form by Silverstein and co-workers.1 Using a route beginning

Conjugate addition-alkylation reactions of lithium dialkyl cuprates to hex-2-enopyrano-4-ulosides (1), hex-3-enopyrano-2-ulosides (2), and hex-1-enopyrano-3-uloses (3) have been investigated. Extensive studies with 1 show that the homogeneous system using the soluble tri-n-butylphosphine copper(I) complex is less satisfactory than the heterogeneous medium in which copper(I) iodide is used. The use of Grignard reagents versus alkyl lithiums has also been investigated, the latter being found preferable. 1,2-Addition was observed in some cases, but conditions were developed to avoid formation of these side products.With α-enones 1 and 2 alkylation is completely stereoselective, the newly introduced alkyl group being in axial orientation. With 3 a complex mixture is obtained from which equatorial and axial adducts can be isolated in approximately equal amounts.

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Die Herstellung des Pheromons (‐)‐a‐MLlltistratin (I) geht von den 3.3,4‐Tri‐des0xy‐Z,4‐cli‐(′‐metliyl‐lylxo‐hexapyrunosiden (VI) aus.

Im Zusammenhang mit der Herstellung von Multistriatinen wie (XV) werden verschiedene im Formelschema aufgeführte Reaktionen an Kohlenhydraten beschrieben und die verschiedenen Stereoisomeren hergestellt.