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.

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.