General approach to the synthesis of polyquinenes via the Weiss reaction. 6. Progress toward the synthesis of dicyclopentapentalenes

Abstract

1) (a) Katz, T.; Rosenberger, M.; OHara, R. K. J. Am. Chem. SOC. 1964,86,249-252. (b) Hafner, K.; Sibs, H. U. Angew. Chem., Znt. Ed. Engl. 1973,12,576-577. Hafner, K.; Dbnges, R.; Goedeck, E.; Kaiser, R. Angew. Chem. 1973,85,362-364. Dbnges, R.; Hafner, K.; Lindner, H.-J. Marty, R. A.; de Mayo, P. J. Am. Chem. SOC. 1971, 93, 3071-3072; Baird, N. C.; West, R. M. J. Am. Chem. SOC. 1971, 93, (2) Butenschh, H.; de Meijere, A. Tetrahedron 1986,42,1721-1729 and references cited therein. Lendvai, T.; Friedl, T.; Butenschbn, H.; Clark, T.; de Meijere, A. Angew. Chem., Znt. Ed. Engl. 1986,25,719-720. 3072-3073. 0022-3263/88/l953-2327$01.50/0 Scheme I W H Scheme I1 9 Z [7.2.1.04J1.08~10]dodeca-l,3,5,7,9(12)-pentaene (2) have been discussed only from a theoretical point of view despite the preparation of the carbon skeletons of these molecules by several group^.^-^ (3) Uggeri, F.; Srikrishna, A,; Eaton, P. E. J. Org. Chem. 1984, 49, 1728-1732. McKervey, M. A.; Vibuljan, P.; Ferguson, G.; Siew, P. J. Chem. Soc., Chem. Commun. 1981,912-914. 0 1988 American Chemical Society cis-bicyclo[3.3.0]octane derivatives from reaction of substituted glyoxals with dimethyl 3-oxoglutarate (Scheme I).This process has now been employed to provide simple entry into the requisite ring systems of the three annulenes, suitably functionalized (OH) for later conversion into 1-3. Controversy exists as to whether polyquinenes such as 1-3 are delocalized, exhibit aromatic Hiickel "type" stability, or exist as alternate hydrocarbons that behave as highly reactive olefinsP16 This controversy provided the impetus for the present study.Earlier, during the synthesis of triquinacene8 the tetraester 6b, which is readily available from glyoxal (4a) and di-tert-butyl3-oxoglutarate (5b), was converted into the bisenol ether. This tetraester could be monoalkylated in >go% yield and converted into triquinacene.8 This ~ (4) Fukunaga, T.; Clement, R. H. (6) Venkatachalam, M.; Deshpande, M. N.; Jawdosiuk, M.; Kubiak, G.; Wehrli, S.; Weiss, U.; Cook, J. M. Tetrahedron 1986,42,1597-1605.

Permethylpentalene Chemistry

“…The hydrolysis‐decarboxylation of 2 proved to be difficult, with the conditions for the analogous process on 1 (1–3 M HCl (aq) , reflux)20 resulting in the extremely slow evolution of CO 2(g) . This has been previously observed for other substituted keto esters of bicyclo[3.3.0]octane 21. In this instance, it can be envisaged that the formation of a tetrahedral intermediate in the A AC 222 process for the hydrolysis under these conditions is severely retarded due to the steric encumbrance within the molecular cleft in which the esters reside.…”

Pentacycloundecane (PCUD)‐Based Cage Frameworks as Potential Energetic Materials: Syntheses and Characterization

“…Compound 21 is the best candidate among all four compounds in terms of their overall performance. Symmetrical polycyclic cage molecules [85][86] with a high-nitrogen content may act as energetic compounds which may be of interest to material and synthetic chemists.…”

Modular Approaches to Cyclopentanoids and their Heteroanalogs

“…Our group successfully reported a practical approach for the preparation of 3,8-dimethyl-2,7-dioxaspiro [4.4]nonane-1,6-dione (81) in good yield. The diastereomeric mixture of spirolactones 81a-c were obtained by the diallylation of ethyl malonate (79) followed by the acid-mediated hydrolysis and subsequent cyclization. The structures of diastereomers 81a-c were confirmed by the NMR spectral data and further supported by the X-ray diffraction studies (Scheme 17).…”

“…Among these, the cis-cisoid-cis-cisoid isomer formed as a major product (Scheme 65). 79 The tricyclic keto olefin 318, on reaction with dichloroketene, derived from trichloroacetyl chloride (319) in the presence of zinc, delivered the corresponding regioiso-Scheme 63 Synthesis of bis-armed spiro derivatives…”

“…Surprisingly, an unprecedented tetraquinane 372 was obtained instead of the expected dehydrative compound when tetraol 371 was reacted with HMPA (Scheme 80). 79 In connection with our interest in the synthesis of new cyclopentanoids, initially we focused on the construction of an important target pentaquinane. For this purpose, we performed a PTSA catalyzed reaction of dione 373 with the mixture of allyl alcohol (103) and 2,2′-dimethoxypropane (374) under reflux in toluene to achieve diallylation.…”