Rhenium Complex as a Useful Catalyst for Acylative Cleavage of Ethers

Abstract

It was found that a rhenium complex such as ReBr(CO)₅ acts as an efficient catalyst for the acylative cleavage of the carbon-oxygen bond of ethers with acyl chloride, giving the corresponding esters in moderate to good yields.

rhenium complex - ethers - acylation - esters - catalysis

References and Notes

<A NAME="RU08310ST-1A">1a</A> Larock RC. Ether Cleavage, In Comprehensive Organic Transformations   2nd ed.:  Wiley-VCH; Weinheim: 1999. 

<A NAME="RU08310ST-1B">1b</A> Bhatt MV. Kulkarni SU. Synthesis  1983,  249 

<A NAME="RU08310ST-1C">1c</A> Burwell RL. Chem. Rev.  1954,  54:  615 

<A NAME="RU08310ST-2">2</A>

It was found that Lewis acids,^³ group 5 or 6 metal complexs,⁴ metals such as Al⁵ and Zn,⁶ and iodine⁷ can be used as a useful catalyst for the transformation. However, many of these methods involve some disadvantages (i) the use of toxic, expensive, and unstable agents, (ii) the formation of mixtures of products, (iii) low yields, and (iv) limitation of the substrates.

<A NAME="RU08310ST-3A">3a</A> Ganem B. Small VR. J. Org. Chem.  1974,  39:  3728 

<A NAME="RU08310ST-3B">3b</A> Ahmad S. Iqbal J. Chem. Lett.  1987,  953 

<A NAME="RU08310ST-3C">3c</A> Iqbal J. Khan MA. Srivastava RR. Tetrahedron Lett.  1988,  29:  4985 

<A NAME="RU08310ST-3D">3d</A> Iqbal J. Srivastava RR. Tetrahedron  1991,  47:  3155 

<A NAME="RU08310ST-3E">3e</A> Oriyama T. Kimura M. Oda M. Koga G. Synlett  1993,  437 

<A NAME="RU08310ST-3F">3f</A> Mimero P. Saluzzo C. Amouroux R. Tetrahedron Lett.  1994,  35:  1553 

<A NAME="RU08310ST-3G">3g</A> Green L. Hemeon I. Singer RD. Tetrahedron Lett.  2000,  41:  1343 

<A NAME="RU08310ST-3H">3h</A> Coles SJ. Costello JF. Draffin WN. Hursthouse MB. Paver SP. Tetrahedron  2005,  61:  4447 

<A NAME="RU08310ST-3I">3i</A> Yadav JS. Reddy BVS. Reddy PMK. Dash U. Gupta MK. J. Mol. Catal. A: Chem.  2007,  271:  266 

<A NAME="RU08310ST-3J">3j</A> Suresh V. Suryakiran N. Rajesh K. Selvam JJP. Srinivasulu M. Venkateswarlu Y. Synth. Commun.  2008,  38:  92 

<A NAME="RU08310ST-4A">4a</A> Guo Q. Miyaji T. Gao G. Hara R. Takahashi T. Chem. Commun.  2001,  1018 

<A NAME="RU08310ST-4B">4b</A> Guo Q. Miyaji T. Hara R. Shen B. Takahashi T. Tetrahedron  2002,  58:  7327 

<A NAME="RU08310ST-5">5</A> Luzzio FA. Bobb RA. Tetrahedron  1999,  55:  1851 

<A NAME="RU08310ST-6A">6a</A> Bhar S. Ranu BC. J. Org. Chem.  1995,  60:  745 

<A NAME="RU08310ST-6B">6b</A> Pasha MA. Myint YY. Ultrason. Sonochem.  2006,  13:  175 

<A NAME="RU08310ST-7A">7a</A> Yadav JS. Reddy BVS. Reddy PMK. Gupta MK. Tetrahedron Lett.  2005,  46:  8493 

<A NAME="RU08310ST-7B">7b</A> Pasha MA. Manjula K. Synth. Commun.  2007,  37:  927 

<A NAME="RU08310ST-8A">8a</A> Nishiyama Y. Kakushou F. Sonoda N. Bull. Chem. Soc. Jpn.  2000,  73:  2779 

<A NAME="RU08310ST-8B">8b</A> Nishiyama Y. Kakushou F. Sonoda N. Tetrahedron Lett.  2005,  46:  787 

<A NAME="RU08310ST-8C">8c</A> Nishiyama Y. Shimoura K. Sonoda N. Tetrahedron Lett.  2008,  49:  6533 

<A NAME="RU08310ST-8D">8d</A> Nishiyama Y. Kaiba K. Umeda R. Tetrahedron Lett.  2010,  51:  793 

Selected papers on using ReBr(CO)₅ as catalyst for C-C bond formation, see:

<A NAME="RU08310ST-9A">9a</A> Zuo W.-X. Hua R. Qiu X. Synth. Commun.  2004,  34:  3219 

<A NAME="RU08310ST-9B">9b</A> Kuninobu Y. Kawata A. Takai K. Org. Lett.  2005,  7:  4823 

<A NAME="RU08310ST-9C">9c</A> Zuo W.-X. Hua R. Tetrahedron Lett.  2007,  63:  11803 

<A NAME="RU08310ST-9D">9d</A> Kuninobu Y. Yu P. Takai K. Chem. Lett.  2007,  36:  1162 

<A NAME="RU08310ST-10">10</A>

We also investigated the reaction of 1a and 2a using other rhenium complexes as a catalyst. The yields of ester 3aa were in slightly lower compared to that of ReBr(CO)₅ (90%), Re₂(CO)₁₀ (71%), MeReO₃ (84%), ReCl₅ (74%), and Re₂O₇ (80%).

<A NAME="RU08310ST-11">11</A>

General Procedure A DCE (3.0 mL) solution of acyl chloride (0.6 mmol), ether (0.5 mmol), and ReBr(CO)₅ (2.5 mol%) was stirred under an atmosphere of nitrogen at 80 ˚C for 2 h. After the reaction was completed, H₂O was added to the reaction mixture and extracted with EtOAc. The organic layer was dried with MgSO₄. The resulting mixture was filtered, and the filtrate was concentrated. Purification of the residue by silica gel column chromatography afforded ester. The structures of the products were assigned by their ^¹H NMR, ^¹³C NMR, and mass spectra.

<A NAME="RU08310ST-12">12</A> Kusama H. Narasaka K. Bull. Chem. Soc. Jpn.  1995,  68:  2379