Chemoselective Oxidation of Alcohols to Aldehydes and Ketones by Iodosobenzene/(Salen) Chromium Complex

Abstract

Various benzylic and allylic alcohols were selectively oxidized to their corresponding aldehydes and ketones by a new Cr(III)(salen) complex I as the catalyst and PhIO as terminal oxidant. The oxidation requires relatively shorter reaction time and produces excellent yields.

Key words

benzylic alcohol - allylic alcohol - Cr(salen) - oxidation - chemoselectivity

Reference

• 1a Canali EN. Sherrington DC. Chem. Soc. Rev.  1999,  28:  85 
• 1b Daly AM. Renehan MF. Gilheany DG. Org. Lett.  2001,  3:  663 
• 1c Kerrigan NJ. Langan IJ. Dalton CT. Daly AM. Bousquet C. Gilheany DG. Tetrahedron Lett.  2002,  43:  2107 
• 1d Baleizao G. Gigante B. Sabater MJ. Garcia H. Corma A. J. Mol. Catal. A: Chem.  2002,  228:  279 
• 2 Jacobsen EN. Pfaltz A. Yamamoto H. Comprehensive Asymmetric Catalysis II   Springer-Verlag; Berlin, Heidelberg: 1999.  Chap. 18.
• 3 Samsel EG. Srinivasan K. Kochi JK. J. Am. Chem. Soc.  1985,  107:  7606 
• 4 Srinivasan K. Michaud P. Kochi JK. J. Am. Chem. Soc.  1986,  108:  2309 
• 5a Zhang W. Loebach JC. Wilson SR. Jacobsen EN. J. Am. Chem. Soc.  1990,  112:  2801 
• 5b Jacobsen EN. Zhang W. Much A. Ecker JR. Deng L. J. Am. Chem. Soc.  1991,  113:  7063 
• 5c Chang S. Galvin JM. Jacobsen EN. J. Am. Chem. Soc.  1994,  116:  6937 
• 5d Brandes BD. Jacobsen EN. J. Org. Chem.  1994,  116:  6937 
• 6a Irie R. Noda K. Ito Y. Matsumoto N. Katsuki T. Tetrahedron lett.  1990,  31:  7345 
• 6b Irie R. Ito Y. Katsuki T. Synlett  1991,  265 
• 6c Hamada T. Irie R. Katsuki T. Synlett  1994,  479 
• 7a O’Mahony CP. McGarrigle EM. Renehan MF. Ryan KM. Kerrigan NJ. Bousquet C. Gilheany DG. Org. Lett.  2001,  3:  3435 
• 7b Ryan KM. Bousquet C. Gilheany DG. Tetrahedron Lett.  1999,  40:  3613 
• 8 Adam W. Gelalcha FG. Saha-Möller CR. Stegmann VR. J. Org. Chem.  2000,  65:  1915 
• 9 Adam W. Hajra S. Herderich M. Saha-Möller CR. Org. Lett.  2000,  2:  2773 

10

General procedure for preparation of catalyst I : To a suspension of bis(3,5-dicholorosalicylidene)ethyl-enediamine [0.775 g (1.9 mmol)] in 50 mL of absolute THF was added suspension of anhydrous chromous chloride [0.307 g (2.5 mmol)] in THF (30 mL) with vigorous stirring under N₂ atmosphere at room temperature (ca. 20 °C) for 1 h. Then the dark brown solution was allowed to reflux in the presence of air for 2 h. The residue was suspended in water (50 mL) and the undissolved yellowish brown color material was collected by filtration and washed with water (3 ¥ 10 mL). After filtration and concentration of the filtrate with evaporator, brown material was precipitated on cooling overnight, which was collected and dried under reduced pressure to afford 0.86 g of the required complex I (yield; 93%), mp 320-325 °C, IR (KBr): 3071, 1615, 1440, 1168, 869 cm^-1. Anal. Calcd. for C₁₆H₁₀Cl₅CrN₂O₂: C, 39.1; H, 2.05; N, 5.7. Found: C, 38.9; H, 2.2; N, 5.4.