Reactions of cyclohexane derivatives in superacids

Abstract

The reactions of menthol with FS0,H-SO, and neomenthyl chloride with SbF,-S0,CIF follow different routes. The first yields a substituted cyclopentyl cation and the second a substituted cyclohexyl cation. Experiments on substituted cyclohexyl chlorides show that replacement of all the hydrogen atoms on the next but one carbon atom to the reaction centre blocks formation of a carbocation. It is suggested that ionisation of an equatorial chlorine atom takes place with assistance from an intramolecular electronic interaction, forming the methyl cyclopentyl carbocation in a synchronous process, rather than stepwise via the cyclohexyl carbocation. Reasons for contrasting behaviour in solvolytic reactions are discussed.

Probing Catalyst Function – Electronic Modulation of Chiral Polyborate Anionic Catalysts

“…Spectral data for alcohol 8r : 1 H NMR (CDCl 3 , 300 MHz) δ 3.88 (dt, 1H, J = 22.4 Hz, 3.3 Hz), 1.70 (d of mult, 2H, J = 12.3 Hz), 1.42 (s, 1H), 1.18 (td, 1H, J = 13.5 Hz, 2.1 Hz), 0.93–1.04 (m, 9H), 0.90 (s, 6H) ppm; 13 C­{1H} NMR (CDCl 3 , 125 MHz) δ 66.1, 51.5, 48.8, 35.2, 32.6, 27.7 ppm. These data match those previously reported for this compound …”

“…These data match those previously reported for this compound. 19 Preparation of Aziridine 24 To Verify Absolute Configuration of Aziridine 23b. Preparation of (2R,3R)-1-Benzhydryl-3cyclohexylaziridine-2-carboxylic Acid (41).…”

Synthesis and Characterization of (−)-1-Menthyl-4,7-dimethylindene and Its Main Group Metal Compounds with Lithium, Sodium, Potassium, and Tin

“…Elemental analyses were performed on a Perkin-Elmer Series II CHNS/O Analyser 2400. (−)-Menthyl chloride, (+)-neomenthyl chloride, (+)-menthylmagnesium chloride, (+)-neomenthylmagnesium chloride, (+)-neomenthyl methanesulfonate, 3-bromoindene, 3-chloro-1-(2‘,5‘-dimethylphenyl)propanone, 4,7-dimethylindanone, indenylmagnesium bromide(THF) 5 , (indenyl)lithium, (4,7-dimethylindenyl)lithium,1a (1-neomenthylindenyl)lithium,1b lithium bis(trimethylsilyl)amide(Et 2 O), and 4,7-dimethylindene were prepared according to published procedures. 3-Chloropropionyl chloride, trifluoromethanesulfonic anhydride, (−)-menthone, dichloro-1,3-bis(diphenylphosphino)propanenickel(II), dichloro-1,1‘-bis(diphenylphosphino)ferrocenepalladium(II)(CH 2 Cl 2 ), indanone, sodium amide, potassium hydride, n -butyllithium, trimethyltin chloride, tri- n -butyltin chloride, boron trifluoride(Et 2 O), 4-toluenesulfonic acid(H 2 O), titanium tetrachloride, cerium trichloride, copper iodide, and anhydrous aluminum trichloride were used as purchased.…”

“…[R]D 25 -61.3°(c 5.7, diethyl ether). 1 H NMR (chloroform-d1, 400 MHz): δ 7.48-7.46 (m, 2 H, H 4,7 ), 7.29-7.16 (m, 2 H, H 5,6 ), 6.18 (m, 1 H, H 2 ), 3.34 (m, 2 H, H 1 ), 2.63 (m, 1 H, H 3′ ), 1.91-0.63 (m, 9 H, H 1′,2′,4′,5′,6′,8′ ), 0.90 (d, 3 J ) 6.4 Hz, 3 H, H 7′/9′/10′ ), 0.88 (d, 3 J ) 6.4 Hz, 3 H, H 7′/9′/10′ ), 0.70 (d, 3 J ) 6.8 Hz, 3 H, H 7′/9′/10′ ). MS (30 °C): m/z 254 (8) (-)-3-Menthylindene (3) from 3-Bromoindene/Ni.…”

“…The product was stored at -28 °C under nitrogen. 1 H NMR (chloroform-d1, 400 MHz): δ 7.04 (m, 2 H, H 5,6 ), 6.40 (t, 3 J ) 2.4 Hz, 1 H, H 2 ), 3.32 (d, 3 J ) 2.4 Hz, 2 H, H 1 ), 2.53 (s, 3 H, H 10/11 ), 2.32 (s, 3 H, H 10/11 ). 13 4,7-Diisopropyl-3-indenyl Trifluoromethanesulfonate (10).…”