ChemInform Abstract: 1,4‐ADDITION OF ANIONS OF ALLYL SULFOXIDES AND ALLYLSULFONE TO 2‐CYCLOPENTENONE

Abstract

Additionen der aus den Sulfoxiden (II) unter der Einwirkung von Li‐diisopropylamid entstehenden Anionen verlaufen regio‐ und stereospezifisch unter Bildung der trans‐1,4‐Addukte (III).

Kinetically controlled, stereoselective formation of vinylic sulfones by conjugate addition of lithiated 3-alkylallylic sulfones to cyclic enones

“…A minor less polar fraction consisted of an inseparable 75:25 mixture of diastereomers of (E)-l-[l'-[(4-methylphenyl)sulfonyl]but-2'-enyl]cyclopent-2-en-l-ol (17) (28 mg, 5%): 1H NMR (major isomer) 1.574 (3 H, dd, J4• 3-= 6.4, J4-2, = 1.9 Hz, H4'), 2.10-2.65 (4 H, m, H4, H5), 2.443 (3 H, s, CH3), 3.807 (1 H, d, JV2, = 10.3 Hz, HI'), 4.300 (1 H, s, OH), 5.17 (1 H, dq, J3,2, = 15.2, j3-4. = 6.4 Hz, H3'), 5.36 (1 H, ddq, J2.3, = 15.2, J2.v = 10.4, J2,4.…”

“…The second fraction was (1RS,1 'SR,2'E,4SR)-4-tert-butoxyl-[l'-[(4-methylphenyl)sulfonyl]but-2 -enyl]cyclopent-2-enol (20) (184 mg, 32%), a colorless oil: SH NMR 1.217 (9 H, s, i-Bu), 1.58 (3 H, dd, J4,3, = 6.3, J4,x = 1.5 Hz, H4'), 1.905 (1 H, dd, = 14.5, = 3.8 Hz, H5a), 2.44 (3 H, s, CH3), 2.888 (1 H, dd, tfsjs.Sa = 14.5, J3ß ß = 7.2 Hz, H5/3), 3.664 (1 H, d, J\<2> -9.8 Hz, HI'), 4.08 (1 H, s, Wh/2 = 7 Hz, OH), 4.527 (1 H, dddd, J436e = 7.0, Jma = 3.5, J43,3 = 2.0, Ji3:2 = 1.5 Hz, H4/3), 5.185 (1 H dd, JW = 15.2, J3,4, = 6.4 Hz, H3'), 5.323 (1 H, ddd, = 15.2, J?v = 10.0, JV4, ='l.5 Hz, H2'), 5.85 (1 H, dd, J32 = 5.4, J34S = 2. Hz, H3), 5.952 (1 H, dd, J%3 = 5.5, J2|4S = 1.2 Hz, H2), 7.29-7.70 (5 H, m, ArH).…”

“…The sulfone (E:Z 81:19) (304 mg, 1.55 mmol) in THF (30 mL) at -70 °C under nitrogen was treated with butyllithium (1.31 mL, 1.3 , 1.71 mol) followed by cyclopent-2-enone (140 mg, 1.71 mmol) to give a pale yellow oil. The crude product was subjected to radial chromatography with 40:60 ethyl acetate-petroleum ether to give the unreacted starting compound (65 mg) and then an inseparable 81:19 mixture of the diastereomers 25 and 26 (268 mg, 79%) of 3-[l'-methyl-3'-{phenylsulfonyl)prop-2'-enyl\cyclopentanone as white prisms, mp 99-101.5 °C, from ethyl acetate-petroleum ether: NMR (major isomer 25) 1.114 ( 3H, d, JMer = 6.72 Hz, CH3), 1.44-1.56 (1 H, m, H4/3), 1.85 (1 H, ddd, J202a = 18.3, J293 = 10.75, =/2S5g = 1.25 Hz, H2/J), 2.05-2.45 (6 H, m, 2 , H3, 4 , H5, HI'), 6.36 (1 H, dd, J3,2, = 15.2, J3, v = 1.1 Hz, H3'), 6.94 (1 H, dd, J2,x = 15.2, J2,x = 8.5 Hz, H2'), 7.50-7.85 (5 H, m, C6H6); (minor isomer 26) 1.143 (3 H, d, e/Mel-= 6.68 Hz, CH3), 1.4-1.6 (1 H, m, H4d), 6.34 (1 H, dd, JS2; = 15.2, J3X = 1.1 Hz, H3'), 6.90 (1 H, dd, = 15.2, J2!X = 8.5 Hz, H2').…”

“…The third fraction, a colorless oil, was a 78:22 mixture of diastereomers 29 and 30 of 3-[l '-methyl-3'-(phenylsulfonyl)prop-2'-enyl]cyclohexanone (163 mg, 25%): 1H NMR (major isomer) 1.063 (3 H, d, =/Mel. = 6.8 Hz, CH3), 1.20-2.43 (10 H, m), 6.323 (1 H, dd, J3,2, = 14.9, J3.y = 1.2 Hz, H3'), 6.891 (1 H, dd, J2'X = 14.9, J2,x = 8.5, Hz, H2'), 7.47-7.90 (5 H, m, C6H5); (minor isomer) 1.067 (3 H, d, </Mel-= 6.8 Hz, CH3), 6.326 (1 H, dd, J3,í2, = 15.1, J3,x = 1.2 Hz, H3'j, 6.902 (1 H, dd, Jrx = 15.1, Jyy = 8.1, Hz, H2'j; HRMS caled for C^H^C^S 292.1133, found 292.1127. The sulfone (E:Z 90:10) (756 mg, 3.86 mmol) in THF (30 mL) at -70 °C was treated with butyllithium (2.1 mL, 2.0 M, 4.24 mmol) and then the enone (410 mg, 4.27 mmol) in THF (5 mL). The solution was warmed to 0 °C, whereupon it was stirred for 1 h and then quenched with aqueous ammonium chloride.…”