Stereochemistry of Allylic Rearrangements. VI. The Ethanolysis and Acetolysis of cis- and trans-5-Methyl-2-cyclohexenyl Chloride¹

Abstract

starch end-point \\ith 0.U5 N sodium thiosulfate. The sealed ampule technique \vas used and reactions werc quenched by placing ampules containing aliquots in an icebath. Aliquots were measured a t 25' with calibrated pipets and 5-ml. calibrated microburets were used for titrations. The titer changed about 1.5 ml. during the 3 5 4 0 % of completion to which the reactions were carefully followed and individual titrations were reproducible to 1 0 . 0 0 4 ml.The rate of reaction of cyclohexyl bromide with iodide ion was followed by potentiometric (Beckman model G potentiometer) titration of 5-ml. aliquots in 50 nil. of water with 0.15 N silver nitrate.Second-order elimination rate constants, k., were calculated from the equation where n is the initial concentration of iodide ion, b the initial dihalide concentration, t the elapied time, and $ the fraction of dihalide that has redcted (z.e., 4 = [ 1 3 -] / b ) a t time t . The values of k2 were corrected for solvent expansion by multiplying by the ratio dZ5,/dt,. The \ d u e s used were: d2j4 0.7870 (by interpolation), dSo4 0.7355, dloo4 0 714 20The values of k2 obtained in this way decreased as the reactions progressed. The rate coilstarits were linear with time to about 307; reaction and initial rate constants were determined by extrapolation to zero time by the method of least squares. Data for typical runs are presented in Tables VI and VII. The second-order constants for the s N 2 reaction of cyclohexyl bromide with iodide ion vxre determined from the relationshipwhere a is the initial concentration of iodidc ioii and of cy-( 2 0 ) Landolt-Btrnstein "Tabellen," J. Springer Verlag, Berlin, ~~ 1923, Vol. I, p. 278.

Benzoquinone-Induced Stereoselective Chloride Migration in (η3-Allyl)palladium Complexes. A Theoretical Mechanistic Study Complemented by Experimental Verification

“…Addition of DDQ to 9 , 11 , and 13 resulted in formation of allyl chloride derivatives 10 , 12 , and 14 , respectively. The products were identified by comparing their 1 H NMR spectra with those of authentic samples. ,, …”

Diastereoselectivity in the Epoxidation of Substituted Cyclohexenes by Dimethyldioxirane1,2

“…3-Chlorocyclohexene (2q) was obtained by purification (GLC) of a technical grade sample and was collected as a colorless liquid …”

“…23 3-Chlorocyclohexene (2q) was obtained by purification (GLC) of a technical grade sample and was collected as a colorless liquid. 30 3-Bromocyclohexene (2r) was obtained by purification (GLC) of a technical grade sample and was collected as a colorless liquid. 31 3-Methyl-2-cyclohexen-1-ol (3a) was prepared by LiAlH4 reduction of 3-methyl-2-cyclohexen-1-one in ether.…”

“…The products were separated by preparative GLC. One of these products was identified as methyl trans-2,3epoxycyclohexanecarboxylate (trans-5h) by comparing its NMR 50 data with those in the literature and on the basis of the following data: a colorless liquid: 1 H NMR (CDCl3) δ 1.25-2.15 (m, 6H), 2.90 (dd, J ) 8.98, 5.86 Hz, 1H), 3.21 (m, 1H), 3.41(d, J ) 3.90 Hz, 1H), 3.73 (s, 3H); 13 C NMR (CDCl3) δ 16.81, 23.69, 23.89, 40.61, 51.86, 51.90, 52.17, 173.73; MS (EI, 70 eV) m/z 156(M + , 0.5), 141(3), 125(28), 124 (16), 113(26), 100(42), 97 (53), 96(83), 95 (19), 87 (35), 79 (58), 71(100), 70 (25), 69 (47), 68(73), 67 (49), 59 (27), 58 (30), 57(10), 55 (57), 41 (49); calcd for C8H12O3: 156.18.…”

Coupling reaction of phenyllithium with allylic chlorides. Stereochemistry of the reaction

“…Distillation of the residue through a spinning band column gave 41.4 g (72%) of allylic alcohol 9: bp 97-98°(lit.10 bp 96-97°for 3-hydroxy-l-butene); glpc analysis (column B) >99% pure; nmr (CC14) 1.19 (d, 3, J = 6.5 Hz, methyl), ca. 3.8 (broad s, 1, hydroxyl, concentration-dependent chemical shift), 4.13 (m, 1, consisting of a quartet, J = 6.5 Hz, each line of which is further split into a doublet of doublets, J = 5.5 and 1.0 Hz, methine), 4.88 (d of d, 1, / = 10.0 and 1.0 Hz, terminal vinyl), and 5.75 (m, 1, consisting of a doublet of doublets, J = 10.0 and 5.5 Hz, each line of which is further split into a 1:1:1 triplet, J = 2.5 Hz, internal vinyl).…”