113. Fused carbon rings. Part VIII. The dehydration of 2-methyl-1-Δ³′-butenylcyclohexanol

THE SYNTHESIS, STRUCTURE PROOF AND AROMATIZATION OF 2-KETO-3-CARBOXY-10-METHYL-Δ1:9, 3:4_ HEXAHYDRONAPHTHALENE1, 2

“…The cis ß-keto acid (XII) actually did yield a diacid, CnHisCq, the melting point of which (190-191°) corresponded closely to that reported (189-190°) for cis-lmethylcyclohexane-1,2-diacetic acid (XXIV) (11,12). The isomeric diacid obtained from XIII, however, melted at 198-199°and thus was clearly different from the sample (m.p.…”

“…The identity of these acids with the hydrogenation products from the dienone acid (II) was established by mixture melting points and by comparisons of the infrared absorption spectra. The fact that these acids indeed differed from each other in the configuration at the ring juncture was shown by decarboxylation, which transformed the 115°isomer into cfs-10-methyl-2-decalone (XIV) (1,8,10,12) and the 130°isomer into ¿rans-lO-methyl-2-decalone (XV) (10).7 Further evidence on the position of the carboxyl group in the two saturated fi-keto acids was sought from the nitric acid oxidation. It was hoped that the presence of the 3-carboxyl group would direct the oxidation between carbons-2 and -3 to give the two stereoisomeric 1-methylcyclohexane-l ,2-diacetic acids.…”

A Case Study in Biomimetic Total Synthesis: Polyolefin Carbocyclizations to Terpenes and Steroids

“…Specifically, 'mild' Brønsted acid cyclization conditions (H 2 SO 4 , AcOH, Ac 2 O, 25 °C or H 3 PO 4 , 140 °C) converted tertiary alcohol 9 to cis-decalin product 10 in 89% yield (Scheme 3). 38 The intermediacy of a tetrasubstituted olefin cannot be excluded given Linstead's finding that the regioisomeric tertiary alcohol of 9 behaves similarly to 9, providing a cis-decalol product (not shown).39…”

Thiyl radical induced cyclizations of dienes. Cyclization of .alpha.-acoradiene, .alpha.-bulnesene, and geranyl acetate to cedrane, patchulane, and cyclogeranyl acetate products

“…m/e 244 (M+); NMR (CDC13) 5.24 (t,=7 = 7 Hz, 1 H), 4.48 (d,«7 = 7 Hz, 2 ), 2.08-2.28 (m, 3 ), 2.04 (s, [8][9] ), 1.68 (s, [3][4] ), 0.96 (doublet of doublets, «7 = 8 and 4 Hz, 6 H). D, E, and F, m/e 244 (M+).…”

“…After stirring for 20 h the mixture was filtered through Celite and concentrated and the residue triturated with five 30-rnL portions of hexane. Concentration and distillation at 120-130 °C (18 mm) gave 0.24 g of 4,4-dicarbomethoxy-6-methylcyclohexene: NMR (CDCI3) 1.05 (d, 3 ), 1.5-3.0 (m, 5 ), 3.80 (s, 6 H), 5.7 (m, 2 H); m/e (rel intensity) 212 (7), 211 (58), 151 (81), 136 (68), 92 (89), 91 (96), 90 (100), 78 (84), 58 (75).…”