A. N. Kasatkin

Stereospecific synthesis of a key synthon for faranal — The trail pheromone of the ant Monomorium pharaonis

An effective scheme is proposed for the synthesis of the methoxymethyl derivative of racemic (erythro)-5-iodo-3,4-dimethylpentan-1-ol (a for obtaining faranal) from methyl (erythro)-3,4,5-trimethylhex-5-enoate — the product of the diastereospecific 1,4-addition of 2,3,-dimethylallylmanganese chloride to methyl crotonate.

σ-Complexes of transition metals in organic synthesis. 9. Reactions of allyl organomanganese compounds with γ-bromine derivatives of esters of α, Β-unsaturated carboxylic acids

The allyl Mn(II) organic compounds R1CH=C(R2)CH2MnCl (R1=H, Me; R2=H, Me, Bu), obtained in situ from Grignard reagents and Li2MnCl4, react with esters of 4-bromocrotonic, (2-bromobutylidene)-, (4-bromo-2-butenylidene)-, (2-bromoisobutylidene) malonic, and (2-bromoheptylidene)cyanoacetic acids in THF at −78 to +20‡C to give derivatives of substituted cyclopropanecarboxylic or cyclopropane-1, 1-dicarboxylic acids. These derivatives contain a fragment of the allyl type. When ethers of 2-(bromomethyl)acrylic, 4-bromo-2-methyl-, and 4-bromo-3-methyl-2-butenoic acids are used, cross-combination products result.

σ-Complexes of transition metals in organic synthesis 8. Coupled addition of allyl MN(II)-organic compounds to esters and nitriles ofα,β-unsaturated carboxylic acids

Allyl Mn(II)-organic compounds R1CH=C(R2)-CH2MnCl (R1=H, Me; R2=H, Me, Bu, PhCH2) react with esters and nitriles of crotonic, trans-2-hexenoic, sorbic, cinnamic, maleic, fumaric, heptylidenemalonic, and trans-(2-butenylidene)malonic acids in THF at−78 to−60°C giving 1,4-addition products. A single diastereoisomer is formed in the case of MeCH=CHCO2Me and PrCH=CHCO2Me.

Transition metal σ-complexes in organic synthesis

Aryl organomanganese compounds ArMnX and Ph3MnLi (Ar=Ph, p-MeC6H4, p-MeOC6H4, p-ClC6H4, p-BrC6H4, α-naphthyl; X=Cl, Br) react with alkenyl iodides RR1C=CR2I (R=H, Pr, Bu, i-Bu, C6H13, CH2=CHCH2, Ph; R1=H, Pr, C5H11; R2=H, Pr, SiMe3) in THF at 0–20°C to give cross-coupling products RR1C=CR2Ar in high yields.

Transition metal σ-complexes in organic synthesis. 4. Cross coupling of allyl esters and allyl aryl sulfones with organotitanium compounds in the presence of palladium complexes

ConclusionsThe reactions of organotitanium compounds PhTi(OPr-i)3 and MeTi(OPr-i)3 with allyl acetates, allyl phenyl ethers, allyl aryl sulfones, and allylic tosylates and mesylates are catalyzed by Pd complexes and lead to the formation of cross-coupling products.