Pyrolysis of β-hydroxy sulfoxides to ketones

New synthetic reactions. Sulfenylations and dehydrosulfenylations of esters and ketones

“…A main thrust of much of this work has been directed toward the preparation of substituted butenolides and a-methylene-butyrolactones from the corresponding saturated precursors.47•63 The alkylation of dianions derived from a-sulfinyl ketones has provided new synthetic approaches to both cyclic and acyclic substituted vinyl ketones.64 One pot alkylationelimination reactions involving the alkylation and subsequent thermolysis of the anions of methyl phenylsulfmylacetate allow for a facile olefination of alkyl halides or -allyl palladium substrates.48•54 •65 The synthesis and elimination of sulfoxides ß to a carbonyl group have been employed to prepare amethylene ketones, acids, and lactones.66 A new ketone synthesis based upon the pyrolysis of /3-hydroxy sulfides appears promising. 67 The direct sulfinylation of ketone enolates with methyl arylsulfinates has also recently been reported. 68 In addition to the oxidation-elimination sequence previously discussed, it is important to note that the -thio esters and ketones which are readily available by direct sulfenylation are valuable synthetic intermediates in and of themselves.i3d•131,69…”

“…X 10 in. silica gel dry column (10% ether in hexane) to yield 1.23 g (87%) of the desired product at Rf = 0.3: ir (CC14) 1739, 1625, 1595; NMR (CC14) 5 6.7-7.9 (11 H, m), 3.80 (3 H, s), 3.60 (3 H, s), 3.3-3.8 (1 H, obscured by the methyl singlets), 3.05 (2 H, br t, / = 8), 2.15 (2 H, m); mass spectrum (m/e, %) 368 (3), 367 (8), 366 (33), 259 (13), 258 (25), 256 (14), 197 (38), 184 (23), 172 (36), 171 (100), 153 (23), 141 (17), 129 (17), 128 (100), 115 (20), 109 (26), 77 (15), 67 (21). Caled for C22H22O3S: 366.1289.…”

“…Mp 94-98 °C; ir (CCI4) 1704; NMR (CC14) 7. 35 (5 H, m), 3.92 (1 H, dd, / = 12.0 Hz, 3.6 Hz), 2.3-3.0 (2 H, m), 1.0-2.3 (16 H, m); mass spectrum (m/e, %) 292 (3), 291 (10) , 290 (45), 263 (3), 262 (14), 218 (6), 149 (15), 137 (5), 136 (7), 135 (8), 123 (26), 112 (5), 111 (10), 109 (21), 101 (28), 97 (25), 96 (11) , 95 (23), 91 (10), 85 (17), 83 (37), 82 (19), 81 (30), 77 (11), 71 (16), 69 (37), 68 (16), 67 (29), 66 (10), 65 (10), 57 (11), 56 (10), 55 (66), 54 (11), 53 (10). Caled for C18H26OS: 290.170425.…”

“…Found: 144.0602. 2-Phenylthiocyclohexanone.75 Ir (CHC13) 1708, 1585; NMR 7.1 -7.4 (5 H, m), 3.68 (1 H, t, J = 5 Hz), 2.8 (1 H, m), 1.4-2.4 (7 H, m); mass spectrum (m/e, %) 206 (67), 110 (100), 69 (23), 41 (38). Caled for C12H14OS: 206.0765.…”

Pericyclic Reactions of Organosulfur Compounds

“…7-101; Grieco and Pogonowski, 1975), and Nokami's route to jS-keto esters (Eq. 7-102; Nokami et al, 1975b). The regioselectivity of olefin formation in sulfoxide pyrolysis has been examined in a variety of acyclic and cyclic systems and is thought to be influenced by steric inter actions, dipole-dipole effects, proton acidity, and double-bond stability (Trost and Leung, 1975;Jones et al, 1976).…”