4-Homoisotwistane, 6,7-exo-trimethylenebicyclo[3.2.1]octane, and homoadamantane as intermediates in Broensted acid catalyzed adamantane rearrangement of tricycloundecanes

Abstract

8]undecane) (3), 6,7-exo-triinethylenebicyclo[3.2.1]octane (4), and homoadamantane (5), together with several, as yet unidentified tricycloundecanes, were discovered to be intermediates in the adamantane rearrangement of 2,3-exo-tetramethylenenorbornane (1) and 2,3-trimethylenebicyclo-[2.2.2]octane (2). 13C nmr spectroscopy was the main tool in the structure determination of 3 and 4. The structure of 4 was further confirmed by comparison with an independently synthesized authentic specimen. Br0nsted acids (trifluoromethanesulfonic acid and sulfuric acid) were found to catalyze the rearrangement of these tricycloundecane precursors with almost quantitative yields of the products, the catalysis being milder and more specific than that by aluminum halides. A high yield synthesis of 3 was accomplished by a selective rearrangement of 2 catalyzed by sulfuric acid, An outline of the reaction scheme was deduced from the product studies of these Br0nsted acid catalyzed rearrangements.Acid-catalyzed isomerization of polycyclic saturated hydrocarbons to adamantanes (so-called adamantane rearrangement) has been widely studied since the discovery of the reaction by Schleyer.1 Elucidation of the mechanism of

Biologically active polycycloalkanes. 2. Antiviral 4-homoisotwistane derivatives

“…3-Hydroxy-4-homoisotwistane (7). A mixture of 0.69 g (0.003 mol) of 3-bromo-4-homoisotwistane (4) in 30 ml of acetone and 20 ml of water was refluxed at 85°for 1 h. The reaction mixture was extracted with two 20-ml portions of petroleum ether.…”

“…Therefore, the C-3 atom of 3 should react much faster than the C-l and C-8 in bromination, that is, an ionic process involving carbocations.14 '15 Hydrolysis of 3-bromo-4-homoisotwistane (4) was quite fast, in accordance with the high stability of its 3-cation. Reflux of 4 in aqueous acetone for 1 h caused a complete hydrolysis of 4 to 4-homoisotwistan-3-ol (7). Neither alkali nor silver ion14 was required as catalyst for the reaction.…”

“…, 1080 cm*1; 7H NMR (CCU) 0.8-2.6 (complex m, 17 H),3.64 (s, 3 H); mass spectrum m/e (rel intensity) 208 (10, M+), 150 (13), 149 (100), 107 (7), 93 (9), 91 (6), 81(14), 79 (10), 67(21), 41(7). Anal.…”

Oxymercuration-demercuration and hydroboration-oxidation of endo-tricyclo[5.2.2.02,6]undeca-3,8-diene. Stereospecific oxymercuration leading to the 4-exo-hydroxy derivative

“…The reaction was then refluxed for an additional 2 hr and worked up in the usual manner to give 5.4 g (92% yield) of solid crude 7. Purification on preparative VPC gave a pure material: mp 101-102°; ir 3280, 3040, 2920, 2860, 1610, 1460, 1440, 1370, 1350, 1290, 1080, 1020, 840, 710 cm'1; NMR 0.8-2.8 (m, 13), 3.8 (m, 1, CHOH), 6.17 (t, 2, CH-CH); mass spectrum m/e (rel intensity) 164 (3, M+), 92 (5), 91 (6), 81 (8), 80 (100), 79 (15), 77 (5), 67 (3), 44 (3).…”

“…(m, 12), 2.02 (s, 1, OH), 4.18 (m, 1, CHOH), 6.12 The mass spectrum of 4 was taken on the Golay GC-MS: m/e (rel intensity) 164 (26, M+), 92 (14), 91 (20), 83 (64), 82 (27), 80 (100), 79 (49), 77 (15), 41 (14), 39 (17). eadorTrieyclo[5.2.2.02 '6]undec-8-en-4-one ( 5) and endo-Tricyclo[5.2,2.02 '6]undec-8-en-3-one (6). The crude product of the oxymercuration-demercuration of 1 was converted to a mixture of eredo-tricyclo[5.2.2.02 '6]undec-8-en-4-one ( 5) and -3-one ( 6) by Jones oxidation.…”