Synthesis and reactions of metallocycles. 6. Stereoselective synthesis of 3,4-dialkyl-substituted aluminocyclopentanes by cyclometallation of α-olefins using trialkylalanes in the presence of Cp2ZrCl2

An efficient method has been developed for the synthesis of a new class of organoaluminum compounds, trans-3,4-dialkyl-substituted aluminocyclopentanes, via the cyclometallation of -olefins using R₃A1 in the presence of catalytic amounts of Cp₂ZrCl₂. Hydrolysis, deuterolysis, and oxidation of the resulting aluminocy-clopentanes generate the corresponding transformation products having exclusively the threo-configuration.For previous communication see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1141–1144, May, 1991.     

Synthesis and transformations of metallocycles. 9. Regioselective and stereoselective synthesis of al-substitutedtrans-3,4-dialkylaluminocyclopentanes catalyzed by (η5-C5H5)2ZrCl2

A new stereoselective method is developed for the synthesis of 1-chloro-, 1-alkoxy-, and 1-N,N-dialkylaminoalumino-cyclopentanes from -olefins, metallic magnesium, and aluminum halides (AlCl₃, RO-AlCl₂, R₂N-AlCl₂) in the presence of catalytic amounts of Cp₂ZrCl₂ (Cp=⁵-C₅H₅). The products from hydrolysis and deuterolysis of the Al-substituted 3,4-dialkylaluminocyclopentanes (ACP) have the threo configuration.For Communication 8, see [1].Institute of Organic Chemistry, Urals Branch, Russian Academy of Sciences, 450054 Ufa. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1393–1397, June, 1992.     

13C NMR Spectra of polycyclic compounds: stereochemistry of spiro(bicyclo[2.2.1]hepta-2,5-diene-7,1′-cyclopropane) dimers

The structures of the dimerization products of spiro(bicyclo[2.2.1]hepta-2,5-diene-7,1-cyclopropane) have been solved using¹³C NMR spectroscopy and their stereochemical assignments made. The methylene carbon atom signals for the spirocyclopropane fragment can be used as diagnostic signals in making the stereochemical assignments.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 559–564, March, 1990.     

Insect pheromones and their analogues

The synthesis has been effected of octa-2E,6E-diene-1,8-diol diisovalerate — the sex pheromone of the Crimean click beetleAgriotes tauricus — by the carboxymethylenation of the readily available 6-methylhept-5-en-2-one, the allyl oxidation of a terminal methyl group, reduction of the ester fraction, and interaction of the diol so obtained with isovaleryl chloride. The required pheromone can also be obtained from available cyclic oligomers of isoprene.     

Cyclomagnesiation of nitrogen-containing 1,2-dienes with grignard compounds catalyzed by Cp<Subscript>2</Subscript>TiCl<Subscript>2</Subscript>

Cyclomagnesiation of nitrogen-containing 1,2-dienes with Grignard compounds in the presence of activated magnesium and Cp₂TiCl₂ as catalyst afforded 2,5-bis(aminoalkylidene)magnesacyclopentanes in high yield.     

Synthesis of substituted cyclopropanes from vinylarenes and esters in the presence of Cl n AlEt3 − n and Cp2ZrCl2 as catalyst

A procedure has been developed for the selective synthesis of 1-alkoxy(cycloalkoxy)-1-alkyl-(cycloalkyl)-2-arylcyclopropanes in up to 75% yield by reaction of vinylarenes with aliphatic and cycloalkylacetic acid esters in the presence of Cl _n AlEt_{3 ? n} and Cp₂ZrCl₂ as catalyst.     

Synthesis of lupane triterpenoids with triphenylphosphonium substituents and studies of their antitumor activity

New derivatives of lupane triterpenoids, viz., 20,29-dihydrobetulinic and 3-epi-20,29-dihydrobetulinic acid derivatives containing triphenylphosphonium fragments as substituents were synthesized. These compound considerably exceed betulinic acid in antitumor activity.