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DOI: 10.1055/s-2004-815977
Scope and Limitations of Lithium-Ethylenediamine-THF-Mediated Cleavage at the α-Position of Aromatics: Deprotection of Aryl Methyl Ethers and Benzyl Ethers under Mild Conditions
Publikationsverlauf
Publikationsdatum:
16. Februar 2004 (online)
Abstract
The scope and limitation of lithium-ethylenediamine-THF-mediated reductive bond cleavage at the α-position of aromatics were examined. Very mild conditions such as lithium metal (5 equiv) and ethylenediamine (7 equiv) in oxygen-free THF were quite effective for the demethylation of aromatic ethers even at as low as -10 °C. Allyl benzyl ethers were also deprotected under these conditions with very little change of the allylic alcohol moiety. Through this study, 2,6-dimethylbenzyl (m-xylylmethyl, MXM) group was developed as an alternative of benzyl group, which is readily cleavable under the above mentioned reductive conditions.
Key words
electron transfer - ethers - lithium - phenols - protective groups
- 1
Birch AJ. Quart. Rev. 1950, 69 - 2
Kaiser EM. Synthesis 1972, 391 -
3a
Sartoretto PA.Sowa FJ. J. Am. Chem. Soc. 1937, 59: 603 -
3b
Kranzfelder AL.Verbanc JJ.Sowa FJ. J. Am. Chem. Soc. 1937, 59: 1488 -
3c
Weber FC.Sowa FJ. J. Am. Chem. Soc. 1938, 60: 94 - 4
Birch AJ. J. Chem. Soc. 1947, 102 - 5
Reggel L.Friedel RA.Wender I. J. Org. Chem. 1957, 22: 891 - 6
Mejer S.Gawecka K.Jablonski L. Roczn. Chem. 1977, 51: 2477 - 7
Jablonski L.Kotlarek W.Mejer S. Bull. Acad. Polon. Sci. Ser. Sci. Chim. 1975, 24: 101 - 8
Garst ME.Dolby LJ.Esfandiari S.Fedoruk NA.Chamberlain NC.Avey AA. J. Org. Chem. 2000, 65: 7098 - 9
Mann FG.Pragnell MJ. J. Chem. Soc. 1965, 4120 - 10
Node M.Ohta K.Kajimoto T.Nishide K.Fujita E.Fuji K. Chem. Pharm. Bull. 1983, 31: 4178 - 11
Nishioka H.Nagasawa M.Yoshida K. Synthesis 2000, 243 - 12
Chakraborti AK.Sharma L.Nayak MK. J. Org. Chem. 2002, 67: 6406 - 13
Hurd CD.Oliver GL. J. Am. Chem. Soc. 1959, 81: 2795 - 14
Eagle DH. J. Org. Chem. 1963, 28: 1703 - 15
Zimmerman HE.Wang PA. J. Am. Chem. Soc. 1993, 115: 2205 - 16
Yus M.Foubelo F.Ferrández JV. Chem. Lett. 2002, 726 - 17
Hwu JR.Wein YS.Leu Y.-J. J. Org. Chem. 1996, 61: 1493 - 18
Hwu JR.Chus V.Schroeder JE.Barrans RE.Khoudary KP.Wang N.Wetzel JM. J. Org. Chem. 1986, 51: 4731 - 19
Groth U.Schölkopf U.Tiller T. Tetrahedron 1991, 47: 2835 - 20
Liu H.-J.Yip J.Shia K.-S. Tetrahedron Lett. 1997, 38: 2253 - 21
Alonso E.Ramón DJ.Yus M. Tetrahedron 1997, 53: 14355 - 22
Shi L.Xia WJ.Zhang FM.Tu YQ. Synlett 2002, 1505 - 23
Makabe H.Kong LK.Hirota M. Org. Lett. 2003, 5: 27 - 25
Brown CA.Yamashita A. J. Am. Chem. Soc. 1975, 97: 891 - 26
Doolittle RE. Org. Prop. Proc. Int. 1981, 13: 179 - 27
Davis R.Muchowski JM. Synthesis 1982, 987 - 28
Soloshonok VA.Tang X.Hruby VJ. Tetrahedron 2001, 56: 6375 - 29
Cardani C.Casnati G.Piazzi F.Cavalleri B. Gazz. Chim. Ital. 1958, 88: 487 - 30
Rang S.Strenze T.Muurisepp M.Eisen O. Org. Mass Spectrom. 1984, 19: 193 - 31
Tateiwa J.Hayama E.Nishimura T.Uemura S. J. Chem. Soc., Perkin Trans. 1 1997, 1923 - 32
Dupont G.Dulou R.Pigerol C. Bull. Chim. Soc. Fr. 1955, 638 - 33
Ali SS.Echner H.Kahn KM.Schroder C.Hasan M.Rahaman A.-U.Voelter W. Z. Naturforsch. B: Chem. Sci. 1994, 49: 1425 - 34
Deck LM.Brazwell EM.Vander Jagt DL.Royer RE. Org. Prep. Proced. Int. 1990, 22: 495 - 35
Konig WA.Faasch H.Heitsch H.Colberg C.Hausen BM. Z. Naturforsch., B: Chem. Sci. 1993, 48: 387 - 36
Tsatsas G.Guioka-Dedopoulou V. Bull. Soc. Chim. Fr. 1964, 10: 2610 - 37
Gonzalez AG.Barrera JB.Rodriguez Perez EM. Z. Naturforsch., C: Biosci. 1991, 46: 12 - 38
Schmalz H.-G.Volk T.Bernicke D.Huneck S. Tetrahedron 1997, 53: 9219 - 39
Miyakoshi T.Togashi H. Synthesis 1990, 407 - 40
Bates RB.Siahaan TJ. J. Org. Chem. 1986, 51: 1432 - 41
Baudin J.-B.Itka B.-W.Hareau G.Julia SA.Lorne R.Pascard C. Tetrahedron 1991, 47: 6655 -
42a
Jankowski P.Marczak S.Masnyk M.Wicha J. J. Organomet. Chem. 1991, 403: 49 -
42b
Zhang Z.-B.Wang Z.-M.Wang Y.-X.Liu H.-Q.Lei G.-X.Shi M. J. Chem. Soc., Perkin Trans. 1 2000, 53 - 43
Cook BR.Reinert TJ.Suslick KS. J. Am. Chem. Soc. 1986, 108: 7281
References
2,6-Dimethylbenzyl group is possible to be abbreviated as DMB, The DMB group, however, is already well know as 2,4-dimethoxybenzyl group. We propose here the MXM group (m-xylylmethyl) to avoid the confusion in future.