Micellar effects on the monohalogenation of n-pentyl phenyl ether


Apr 26, 1977 - rotary evaporated again. The dark semisolid residue was recrystallized four times from minimum benzene to give 137 mg (42%) of colorles...
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3298 J. Org. Chem., Vol. 42, No. 20, 1977 tion barrier for the twist must exceed the barrier for trifluoroacetate addition to the central carbon atom.

Notes application of micellar catalysis has received limited attention,2 although stereochemical control has been the subject of several investigation^.^ If a substrate with several potential reaction sites is solubilized by a micelle in a specific manner, it is conceivable that some control of regioselectivity might accompany micellar catalysis of a given reaction. We have examined the ability of micellar catalysis to influence the regioselectivity of two electrophilic aromatic substitution reactions of n-pentyl phenyl ether ( lL4Ether 1 n-C,H,,O

a 9

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Experimental Section The instrumentation used in this work has been previously described.2,3,7 Preparation of 3. A 303-mg sample of phosphonic acid la7in 5.8 mL of TFA was heated to' 75 "C for 5 days, after which 'H NMR indicated no starting material and -85% pure 3.5 The burgandy colored solution was rotary evaporated, dissolved in 5 mL of benzene, then rotary evaporated again. The dark semisolid residue was recrystsllized four times from minimum benzene to give 137 mg (42%) of colorless 3, mp 167-168 O C . Its lH NMR spectrum is given in the text: IR (KBr) 1720 cm-'; MS (20 eV) m/e (re1absorbance) 250 (13), 179 (12), 152 (97), 137 (loo), 122 (47), 99 (52),57 (48). Anal. Calcd for CllH2304P: C, 52.78; H, 9.26. Found: C, 52.76; H, 9.20. Kinetics measurements were done by 'HNMR integration of the intensity of the doublet in la compared to the doublet in 3. In the case of TFA-dl, 1H NMR peak heights in the tert-butyl region were used. Registry No.--la, 420i37-76-3;3,63088-99-3;TFA, 76-05-1.

References and Notes (a)T. L. Jacobs and R. C. Kammerer. J. Am. Chem. Soc., 96,6213 (1974); (b) M. C. Findlay, W. L. Waters, and M. C. Caserio, J. Org. Chem., 36, 275 (1971); (c)R. D. Each, J. Am. Chem. SOC., 01, 1771 (1969); (d) see, for example,T. L. Jacobs, arid R. N. Johnson, ibid., 82, 6397 (1960); (e)A. V. Fedorova and A. A. Petrov, J. Gen. Chem. USSR,32, 1740 (1962);(f) allene itself undergoes terminal protonation in the gas phase: D. H. Aue, W. R . Davidson, and M. T. Bowers, J. Am. Chem. SOC.,98,6700 (1976). (2) R. S.Macomber and E. R . Kennedy, J. Org. Chem., 41,3191 (1976), and references cited therein. (3) R. S. Macomber, J. Am. Chem. SOC.,99,3072 (1977). (4) MCB reagent, used without further drying. (5) Although