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Ring closure reactions O 0130Dzhemilev Reaction in the Synthesis of Five-Membered Sulfur and Selenium Heterocycles. -Cyclometalation of allenes like (I) and (V), alkynes like (VIII) or simple alkenes with organoaluminum or organomagnesium reagents, followed by reaction with elemental sulfur or selenium, provides a one-pot access to a variety of thiophene or selenophene derivatives. -(D'YAKONOV*, V. A.; IBRAGIMOV, A. G.; KHALILOV, L. M.; MAKAROV, A. A.; TIMERKHANOV, R. K.; TUKTAROVA, R. A.; TRAPEZNIKOVA, O. A.; GALIMOVA, L. F.; Chem. Heterocycl.

A one-pot methods were developed for the synthesis of five-membered sulfur and selenium heterocycles based on the consecutive cyclometallation of olefins, allenes, and acetylenes using alkyl and haloalkyl derivatives of Al and Mg in the presence of catalytic amounts of titanium and zirconium complexes to give the corresponding alumina-and magnesacarbocycles in situ, which, without further purification, were introduced into reaction with sulfur or selenium, leading to various tetrahydrothiophenes, thiophenes, tetrahydroselenophenes, and selenophenes.Thiophene is separated from the coking products of mineral coal or obtained by the thermal reaction of C 4 -hydrocarbons with sulfur, hydrogen sulfide, and SO 2 [1-3]. One of the most popular synthetic methods for the preparation of tetrahydrothiophenes and selenophenes is a method based on use of the Yur'ev reaction [4,5].Along with these methods, the synthesis of five-membered heterocycles by means of replacing transition metal atoms, in particular, the zirconium atom in zirconacyclopentanes, zirconacyclopentenes, and zirconacyclopentadienes by sulfur and selenium atoms, has been found feasible [6][7][8][9]. Unfortunately, this method has not found common use due to the need to employ stoichiometric amounts of the zirconacycloalkanes and the difficulty in preparing these organometallic precursors.The reactions of metallacycloalkanes, prepared in situ using nontransition metals, aluminacyclopentanes [10-12], magnesacyclopentanes [13,14], and their derivatives prepared in situ by the Dzhemilev reaction by means of the catalytic cycloalumination and cyclomagnesation of unsaturated compounds using alkyl Mg and Al derivatives by the action of catalysts derived from Ti and Zr complexes, with S 8 and Se hold promise for the synthesis of five-membered heterocycles (Scheme 1). _______ * Dedicated to Academician B. A. Trofimov of the Russian Academy of Sciences on the occasion of his seventieth jubilee.

Catalytic cycloalumination of cyclonona 1,2 diene upon treatment with Et 3 Al and EtAlCl 2 in the presence of Cp 2 ZrCl 2 , leading to 10 ethyl 10 aluminabicyclo[7.3.0 1,9 ]dodec 8 ene (1) and 11 ethyl 11 aluminatricyclo[10.7.0 1,12 .0 2,10 ]nonadeca 9,12 diene, respectively, was ac complished in high yields. A possibility for the selective transformation of compound 1 to 1 allyl 9 (pent 4 enyl)cyclonon 1 ene and 10 hydroxybicyclo[7.3.0 1,9 ]dodec 8 ene in one pre parative step was demonstrated.Reaction of catalytic cycloalumination of olefins (Scheme 1) and acetylenes, discovered in 1989, 2 is widely used in the synthesis of three and five membered organo aluminum compounds. 3-8 There is no information on the involvement of conjugated 1,3 dienes into this re action. Scheme 1In order to broaden the scope of application of the reaction indicated above, as well as to elaborate a one pot method for the synthesis of the earlier poorly available bi and tricyclic aluminum containing carbocycles, we stud ied the reaction of cyclonona 1,2 diene with Et 3 Al and EtAlCl 2 in the presence of Cp 2 ZrCl 2 as the catalyst, which shows the high activity and selectivity in cycloalumination of unsaturated compounds.We found out that the reaction of cyclonona 1,2 diene with excess of Et 3 Al under previously opti mized 9,10 conditions (5 mol.% Cp 2 ZrCl 2 , 4 h, hexane) with high regioselectivity (>95%) leads to 10 ethyl 10 aluminabicyclo[7.3.0 1,9 ]dodec 8 еne (1) in >85% yield (Scheme 2). Scheme 2 R = H (2), D (3)Structures of compound 1, the products of its hy drolysis (2) and deuterolysis (3) were established by 1 Н and 13 С NMR spectroscopy and chromato mass spec trometry.In the 13 С NMR spectrum of compound 1, character istic of organoaluminum compounds (OAC) upfield sig nals of α carbon atoms at δ 0.8 and 18.2, which are broad ened due to the quadruple relaxation on the 27 Al nuclei (I27 Al = 5/2), are observed. In addition, there are reso nance lines of carbon atoms of a double bond at δ 142.4 and 166.9 in the spectrum, which are related to С(8) and С(9) atoms of the tri substituted double bond in vinylic position to the Аl atom. 9-11 * For Part 32 see Ref. 1.

Catalytic intermolecular cycloalumination of cyclic 1,2 dienes with terminal allenes or disubstituted acetylenes mediated by EtAlCl 2 in the presence of complexes based on transition metals was accomplished. The yield of unsaturated bicyclic aluminacarbocycles was up to 85%.