2,4-Cyclohexadien-1-ones in organic synthesis. Intramolecular Diels-Alder reactivity and the oxa-di-.pi.-methane photorearrangement of Diels-Alder adducts

Abstract

h a 92% yield of 2-octanol is determined by GC. The flask is cooled to room temperature, and the reaction mixture is treated with water (4 mL) and filtered through Celite. The solvent is removed under reduced pressure and the product purified by silica gel column chromatography and distillation [10.5 g, 81% isolated yield, bp 85 °C (18 torr)]. 2-Octanol: IR (neat, absorptions in cm"1) 3400 (br); NMR (60 MHz, CDC13, values from internal Me4Si) 3.8 (m, 1 ), 1.9 (s, 1 H, OH), 1.35 (m, 10 ), 1.2 (t, 3 H), 0.9 (t, 3 H); MS (70 eV, m/e, relative intensity) 130 (M+, traces), 57 (7), 55 (16), 43 (20), 45 (100).Acknowledgment. This work was supported by the Italian C.N.R. (Progetto Finalizzato Chimica Fine e Se-condaria).

Synthetic Aspects of the Di-π-methane Rearrangement

“…The synthetic utility and generality of the ODPM reaction of bicyclo[2.2.2]octenone is illustrated by the examples collected in Table , including yields and references. ,,− ,− However, it should be pointed out that there are limitations in the type of substitution that can be present in the bicyclo[2.2.2]octenone skeleton. Demuth has summarized the influence of substitution by electron-acceptor and electron-donor groups on the outcome of the reaction.…”

“…[109][110][111][112][113][115][116][117][118][119][120][121][122] However, it should be pointed out that there are limitations in the type of substitution that can be present in the bicyclo[2.2.2]-octenone skeleton. Demuth has summarized the influence of substitution by electron-acceptor and electron-donor groups on the outcome of the reaction.…”

Generation and Reactions of ε-Carbonyl Cations via Group 13 Catalysis

“…Bromination was conducted with methods derived from those described by Snead [ 34 ]. Methyl 3-(2-methylphenyl)acrylate 11 (1.1761 g, 4.2 mmol) and N-bromosuccinimide (1.6947 g, 9.522 mmol) were heated to reflux in chloroform (35 mL).…”

Generation and intramolecular cyclization of α-phenylsulfenyl and α-alkylsulfenyl radicals

“…Found: C,71.95;H,6.63. (10). To a solution of 0.38 mL (I.3 retool) of tributylphosphine (85%) in 3 mL of THF was added 269 mg (1.3 mmol) of N-phenylsulfenylsuccinimide.…”

“…According to Method B for the preparation of 13, the reaction of 284 mg (0.97 mmol) of 50 with 0.15 mL ( 1.16 retool) of 5-iodopentene gave 263 mg (75%) of 51 as a pale yellow liquid. This material is a 4/1 mixture of two diastereomers: IR (neat) 3068,2939,2912,2863,1635,1579,1473,1434,1380,1364,1279,1167,1086,1065,1024,989,911,860,747,690 (10). According to the procedure for the preparation of cis-lO, the reaction of 49 mg (0.49 mmol) of cis-2-methylcylopentanol, e3 183 I.tL (0.64 mmol) of tributylphosphine and 152 mg (0.74 mmol) of N-phenylsulfenylsuccinimide 22 gave 16 mg (17%) of trans-lO as a pale yellow liquid: IR (neat) 3057,2954,2866,1582,1478,1449,1435,1092,1025,737,690 General procedure for radical cyclization reactions.…”