Efficient and Chemoselective Deoxygenation of Amine N-Oxides Using Polymethylhydrosiloxane [1]

Abstract

Deoxygenation of aromatic and aliphatic amine N-oxides to the corresponding amines is achieved under mild conditions. The reagent combination employed for this transformation is polymethylhydrosiloxane (PMHS) in the presence of either tetrakis (triphenylphosphine) palladium (0) [Pd(PPh₃)₄], titanium (IV) isopropoxide [Ti(i-PrO)₄] or palladium on carbon (Pd/C).

amine N-oxides - polymethylhydrosiloxane - palladium catalysis - titanium(IV)isopropoxide

References

<A NAME="RD23901ST-1">1</A>

IICT Communication No. 4744.

<A NAME="RD23901ST-2A">2a</A> Ochiai E. J. Org. Chem.  1953,  18:  534 

<A NAME="RD23901ST-2B">2b</A> Ochiai E. In Aromatic Amine Oxide   Elsevier; Amesterdam: 1967.  p.184 

<A NAME="RD23901ST-3">3</A> Ochiai E. Proc. Imp. Acad. (Tokyo)  1943,  19:  307 ; Chem. Abs. 1947, 41, 5880

<A NAME="RD23901ST-4">4</A> Hayashi E. Iijima C. Yakugaku Zasshi.  1962,  82:  1093 

<A NAME="RD23901ST-5">5</A> Hamana M. J. Pharm. Soc. Jpn.  1952,  71:  263 

<A NAME="RD23901ST-6A">6a</A> Emerson TR. Rees CW. J. Chem. Soc.  1962,  1917 

<A NAME="RD23901ST-6B">6b</A> Howard E. Olszewski WF. J. Am. Chem. Soc.  1959,  81:  1483 

<A NAME="RD23901ST-7A">7a</A> Bonini BF. Maccagnani G. Mazzanti G. Pedrini P. Tetrahedron Lett.  1979,  20:  1799 

<A NAME="RD23901ST-7B">7b</A> Olah GA. Arvanaghi M. Vankar YD. Synthesis  1980,  660 

<A NAME="RD23901ST-7C">7c</A> Achremowicz L. Tetrahedron Lett.  1980,  21:  1675 

<A NAME="RD23901ST-7D">7d</A> Morita T. Kuroda K. Okamoto Y. Sakurai H. Chem. Lett.  1981,  921 

<A NAME="RD23901ST-8A">8a</A> Kroehnke F. Schaefer H. Chem. Ber.  1962,  95:  1098 

<A NAME="RD23901ST-8B">8b</A> Abramovitch RA. Adams KHA. Can. J. Chem.  1961,  39:  2134 

<A NAME="RD23901ST-9">9</A> Den Hertog HJ. Overhoff J. Recl. Trav. Chim.  1950,  69:  468 

<A NAME="RD23901ST-10">10</A> McCall JM. TenBrink RE. Synthesis  1975,  335 

<A NAME="RD23901ST-11A">11a</A> Homaidan FR. Issidorides CH. Heterocycles  1981,  16:  411 

<A NAME="D23901ST-11B">11b</A> George J. Chandrasekaran S. Synth. Commun.  1983,  13:  495 

<A NAME="RD23901ST-12">12</A> Hayashi E. Yamanaka H. Shimizu K. Chem. Pharm. Bull.  1958,  6:  323 

<A NAME="RD23901ST-13">13</A> Geroge A. Olah GA. Arvanaghi M. Vankar YD. Synthesis  1980,  660 

<A NAME="RD23901ST-14">14</A> Konwar D. Boruah RC. Sandhu JS. Synthesis  1990,  337 

<A NAME="RD23901ST-15">15</A> Tokitoh N. Okazaki T. Chem. Lett.  1985,  1517 

<A NAME="RD23901ST-16">16</A> Balicki R. Synthesis  1989,  645 

<A NAME="RD23901ST-17">17</A> Barton DHR. Fekih A. Lusinchi X. Tetrahedron Lett.  1985,  38:  4603 

<A NAME="RD23901ST-18">18</A> Akita Y. Misu K. Watanabe T. Ohta A. Chem. Pharm. Bull.  1976,  24:  1839 

<A NAME="RD23901ST-19">19</A> Balicki R. Kaczmarek L. Malinowski M. Synth. Commun.  1989,  19:  897 

<A NAME="RD23901ST-20">20</A> Kano S. Tanaka Y. Hibino S. Heterocycles  1980,  14:  39 

<A NAME="RD23901ST-21">21</A> Handa Y. Inanaga J. Yamaguchi M. J. Chem. Soc., Chem. Commun.  1989,  298 

<A NAME="RD23901ST-22">22</A> Nicolaou KC. Koumbis AE. Snyder SA. Simonsen KB. Angew. Chem. Int. Ed.  2000,  39:  2529 

<A NAME="RD23901ST-23">23</A> Wang Y. Espenson JH. Org. Lett.  2000,  2:  3525 

<A NAME="RD23901ST-24">24</A> Yadav JS. Reddy BVS. Reddy MM. Tetrahedron Lett.  2000,  41:  2663 

<A NAME="RD23901ST-25">25</A> Aoyagi Y. Abe T. Ohta A. Synthesis  1997,  891 

<A NAME="RD23901ST-26A">26a</A> Chandrasekhar S. Reddy CR. Rao RJ. Synlett  2001,  1561 

For an exhaustive review on PMHS, see:

<A NAME="RD23901ST-27A">27a</A> Lawrence NJ. Drew MD. Bushell SM. J. Chem. Soc., Perkin Trans. 1  1999,  3381 

<A NAME="RD23901ST-27B">27b</A> Nitzche S. Wick M. Angew Chem.  1957,  69:  96 

<A NAME="RD23901ST-27C">27c</A> Mimoun H. Laumer JYS. Giannini L. Scopelliti R. Floriani C. J. Am. Chem. Soc.  1999,  121:  6158 

<A NAME="RD23901ST-27D">27d</A> Verdager X. Lange UEW. Buchwald SL. Angew. Chem. Int. Ed.  1998,  37:  1103 

<A NAME="RD23901ST-27E">27e</A> Lopez RM. Fu GC. Tetrahedron  1997,  53:  16349 

<A NAME="RD23901ST-27F">27f</A> Breeden SW. Lawrence NJ. Synlett  1994,  833 

<A NAME="RD23901ST-27G">27g</A> Drew MD. Lawrence NJ. Fontaine D. Sehkri L. Synlett  1997,  989 

<A NAME="RD23901ST-27H">27h</A> Mimoun H. J. Org. Chem.  1999,  64:  2582 ; and references cited therein

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Spectroscopic data of the products(4e): ¹H NMR (CDCl₃): δ 2.56-2.38 (m, 4 H), 2.04 (m, 1 H), 1.9 (m, 1 H), 1.78-1.6 (m, 4 H), 1.55-1.15 (broad m, 8 H), 0.96-0.85 (d, 3 H, J = 7 Hz); IR (Neat): 2927, 2856, 1459, 1283, 772 cm^-1; MS (m/z): 167 (M⁺); Anal. Calcd. for C₁₁H₂₁N: C, 78.98; H, 12.65. Found: C, 79.01; H, 12.63.(4f1): ¹H NMR (CDCl₃): δ 7.41-7.02 (m, 5 H), 6.58-6.44 (d, 1 H, J = 17.6 Hz), 6.3 (m, 1 H), 3.14-3.06 (d, 2 H, J = 6.1 Hz), 2.51-236 (m, 4 H), 1.7-1.54 (m, 4 H); IR (Neat): 2964, 2856, 143, 1360, 759 cm^-1; MS (m/z): 187 (M⁺); Anal. Calcd. for C₁₃H₁₇N: C, 83.37; H, 9.15. Found: C, 83.34; H, 9.12.(4g1): ¹H NMR (CDCl₃): δ 8.3-8.12 (dd, 2 H, J = 8.4, 16.8 Hz), 7.72-7.46 (dd, 2 H, J = 8.4, 16.8 Hz), 3.68 (s, 2 H), 2.58-2.46 (m, 4 H), 1.88-1.76 (m, 4 H); IR (Neat): 2966, 2797, 1519, 1346, 849 cm^-1; MS (m/z): 206 (M⁺); Anal. Calcd. for C₁₁H₁₄N₂O₂: C, 64.06; H, 6.84. Found: C, 64.08; H, 6.86.(4h1): ¹H NMR (CDCl₃): δ 7.42-7.3 (m, 5 H), 7.26-7.14 (dd, 2 H, J = 8.2, 14.3 Hz), 6.96-6.8 (dd, 2 H, J = 8.2, 14.3 Hz), 5.2 (s, 2 H), 3.5 (s, 2 H), 2.54-2.4 (m, 4 H), 1.8-1.64 (m, 4 H); IR (Neat): 2963, 2801, 1453, 1232, 771 cm^-1; MS (m/z): 267 (M⁺); Anal. Calcd. for C₁₈H₂₁NO: C, 80.86; H, 7.92. Found: C, 80.85; H, 7.91.