Abstract
A combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane
(PMHS) facilitates the room-temperature reduction of aromatic nitro compounds to anilines.
These reactions tend to be quick (30 min), high-yielding, and tolerate a range of
other functional groups. Replacement of PMHS/KF with triethylsilane allows for the
reduction of aliphatic nitro compounds to their corresponding hydroxylamines. Depending
on the substrate, both conditions can allow for the in situ conversion of the product
amines into amides, sulfonamides, and carbamates.
Key words
reduction - amines - nitro compounds - palladium - silicon hydride - hydroxylamines
References
<A NAME="RC04506SS-1A">1a </A>
Ono N.
The Nitro Group in Organic Synthesis
Wiley-VCH;
Weinheim:
2001.
<A NAME="RC04506SS-1B">1b </A>
Adams JP.
J. Chem. Soc., Perkin Trans. 1
2002,
2586
<A NAME="RC04506SS-2">2 </A>
Olah GA.
Malhotra R.
Narang SC.
Nitration: Methods and Mechanisms
Feuer H.
VCH;
Weinheim:
1989.
For Michael reactions, see:
<A NAME="RC04506SS-3A">3a </A>
Evans DA.
Seidel D.
J. Am. Chem. Soc.
2005,
127:
9958 ; and references cited therein
<A NAME="RC04506SS-3B">3b </A>
Okino T.
Hoashi Y.
Furukawa T.
Xu X.
Takemoto Y.
J. Am. Chem. Soc.
2005,
127:
119
<A NAME="RC04506SS-3C">3c </A>
Ishii T.
Fujioka S.
Sekiguchi Y.
Kotsuki H.
J. Am. Chem. Soc.
2004,
126:
9558
<A NAME="RC04506SS-3D">3d </A>
Ooi T.
Doda K.
Maruoka K.
J. Am. Chem. Soc.
2003,
125:
9022
<A NAME="RC04506SS-3E">3e </A>
Betancort JM.
Barbas CF.
Org. Lett.
2001,
3:
3737
<A NAME="RC04506SS-3F">3f </A>
List B.
Projarliev P.
Martin HJ.
Org. Lett.
2001,
3:
2423
For Henry reactions, see:
<A NAME="RC04506SS-4A">4a </A>
Evans DA.
Seidel D.
Rueping M.
Lam HW.
Shaw JT.
Downey CW.
J. Am. Chem. Soc.
2003,
125:
12692
<A NAME="RC04506SS-4B">4b </A>
Trost BM.
Yeh VSC.
Ito H.
Bremeyer N.
Org. Lett.
2002,
4:
2621
<A NAME="RC04506SS-4C">4c </A>
Sasai H.
Tokunaga T.
Watanabe S.
Suzuki T.
Itoh N.
Shibasaki M.
J. Org. Chem.
1995,
60:
7388
<A NAME="RC04506SS-4D">4d </A>
Christensen C.
Juhl K.
Hazell RG.
Jørgensen KA.
J. Org. Chem.
2002,
67:
4875
For Aza-Henry examples, see:
<A NAME="RC04506SS-4E">4e </A>
Nugent BM.
Yoder RA.
Johnston JN.
J. Am. Chem. Soc.
2004,
126:
3418
<A NAME="RC04506SS-4F">4f </A>
Okino T.
Nakamura S.
Furukawa T.
Takemoto Y.
Org. Lett.
2004,
6:
625
<A NAME="RC04506SS-4G">4g </A>
Knudsen KR.
Risgaard T.
Nishiwaki N.
Gothelf KV.
Jørgensen KA.
J. Am. Chem. Soc.
2001,
123:
5843
<A NAME="RC04506SS-5">5 </A> For asymmetric conjugate additions, see:
Mampreian DM.
Hoveyda AH.
Org. Lett.
2004,
6:
2829 ; and references cited therein
<A NAME="RC04506SS-6A">6a </A>
Kabalka GW.
Verma RS. In
Comprehensive Organic Synthesis
Vol. 8:
Trost BM.
Fleming I.
Pergamon;
Oxford:
1991.
p.363-379
<A NAME="RC04506SS-6B">6b </A>
Larock RC.
Comprehensive Organic Transformations: A Guide to Functional Group Preparation
Wiley-VCH;
Weinheim:
1999.
2nd ed..
p.821-828
For selected examples of newly developed nitro reductions being employed by others,
see:
<A NAME="RC04506SS-7A">7a </A>
Jacobsen MF.
Moses JE.
Adlington RM.
Baldwin JE.
Org. Lett.
2005,
7:
641
<A NAME="RC04506SS-7B">7b </A>
Camerel F.
Ulrich G.
Ziessel R.
Org. Lett.
2004,
6:
4171
<A NAME="RC04506SS-7C">7c </A>
Berque-Bestel I.
Soulier J.-L.
Giner M.
Rivail L.
Langlois M.
Sicsic S.
J. Med. Chem.
2003,
46:
2606
<A NAME="RC04506SS-8A">8a </A>
Vorbrüggen H. In Silicon-Mediated Transformations of Functional Groups
Wiley-VCH;
Weinheim:
2004.
<A NAME="RC04506SS-8B">8b </A>
The Chemistry of Organic Silicon Compounds, Part 1 & 2
Patai S.
Rappoport Z.
Wiley;
New York:
1989.
<A NAME="RC04506SS-8C">8c </A>
Nagai Y.
Org. Prep. Proced. Int.
1980,
12:
13
<A NAME="RC04506SS-9A">9a </A>
Andrianov KA.
Sidorov VI.
Filimonova MI.
Zh. Obshch. Khim.
1977,
47:
485 ; Chem. Abstr. 1977, 86, 190078
<A NAME="RC04506SS-9B">9b </A>
Andrianov KA.
Tartakovskaya LM.
Shapiro BI.
Zh. Obshch. Khim.
1972,
42:
176 ; Chem. Abstr. 1972, 77, 47990
<A NAME="RC04506SS-9C">9c </A>
Andrianov KA.
Sidorov VI.
Tartakovskaya LM.
Anpilogova AI.
Nepomnina VV.
Pushchevaya KS.
Dokl. Akad. Nauk.
1970,
195:
352 ; Chem. Abstr. 1971, 74, 53900
<A NAME="RC04506SS-10">10 </A>
Lipowitz J.
Bowman SA.
J. Org. Chem.
1973,
38:
162
<A NAME="RC04506SS-11">11 </A>
Blum J.
Bitan G.
Marx S.
Vollhardt KPC.
J. Mol. Catal.
1991,
66:
313
For reviews on PMHS as a reagent for organic synthesis, see:
<A NAME="RC04506SS-12A">12a </A>
Lawrence NJ.
Drew MD.
Bushell SM.
J. Chem. Soc., Perkin Trans. 1
1999,
3381
<A NAME="RC04506SS-12B">12b </A>
Lavis JM.
Maleczka RE.
Polymethylhydrosiloxane (PMHS) , In EROS-Electronic Encyclopedia of Reagents for Organic Synthesis
Paquette LA.
Crich D.
Fuchs PL.
Wipf P.
Wiley;
New York:
2003. [Online]
<A NAME="RC04506SS-13">13 </A>
Rahaim RJ.
Maleczka RE.
Org. Lett.
2005,
7:
5087
<A NAME="RC04506SS-14">14 </A> Nitro group reductions by tin hydrides generated in situ from PMHS reductions
of stannoxanes or alkoxystannanes have been reported:
Nitzsche LS.
Wick M.
Angew. Chem.
1957,
69:
96
<A NAME="RC04506SS-15">15 </A>
Brinkman HR.
Miles WH.
Hilborn MD.
Smith MC.
Synth. Commun.
1996,
26:
973
<A NAME="RC04506SS-16A">16a </A>
Terstiege I.
Maleczka RE.
J. Org. Chem.
1999,
64:
342
<A NAME="RC04506SS-16B">16b </A>
Maleczka RE.
Terrell LR.
Clark DH.
Whitehead SL.
Gallagher WP.
Terstiege I.
J. Org. Chem.
1999,
64:
5958
<A NAME="RC04506SS-16C">16c </A>
Gallagher WP.
Terstiege I.
Maleczka RE.
J. Am. Chem. Soc.
2001,
123:
3194
<A NAME="RC04506SS-16D">16d </A>
Gallagher WP.
Maleczka RE.
J. Org. Chem.
2005,
70:
841
<A NAME="RC04506SS-16E">16e </A>
Lee K.
Gallagher WP.
Toskey EA.
Chong W.
Maleczka RE.
J. Organomet. Chem.
2006,
691:
1462
<A NAME="RC04506SS-17">17 </A>
Rahaim RJ.
Maleczka RE.
Tetrahedron Lett.
2002,
43:
8823
<A NAME="RC04506SS-18A">18a </A>
Rahaim RJ.
Maleczka RE.
A Versatile and Mild Reducing Method of Activated Alkenes, Alkynes, Halides, Nitro
Groups, and Benzylic Oxygens via a Combination of Pd(OAc)
2
, Poly(methylhydrosiloxane), and Aqueous KF
Presented at the 37th Organosilicon Symposium;
Philadelphia USA:
May 20-22, 2004.
p.Poster P-35
<A NAME="RC04506SS-18B">18b </A>
Maleczka RE.
Rahaim RJ.
Teixeira RR.
Tetrahedron Lett.
2002,
43:
7087
<A NAME="RC04506SS-19A">19a </A>
Chauhan BPS.
Rathore JS.
Bandoo T.
J. Am. Chem. Soc.
2004,
126:
8493
For related observations see:
<A NAME="RC04506SS-19B">19b </A>
Fowely LA.
Michos D.
Luo X.-L.
Crabtree RH.
Tetrahedron Lett.
1993,
34:
3075
<A NAME="RC04506SS-19C">19c </A>
Tour JM.
Pendalwar SL.
Cooper JP.
Chem. Mater.
1990,
2:
647
<A NAME="RC04506SS-20">20 </A>
PMHS is a by-product of the silicone industry.
<A NAME="RC04506SS-21">21 </A> PMHS can be stored on the bench for long periods of time (years), and no extraordinary
measures are needed when measuring out or using this reagent. It also is less air-
and moisture-sensitive than other siloxanes, see:
Yactine B.
Ganachaud F.
Senhaji O.
Boutevin B.
Macromolecules
2005,
38:
2230
<A NAME="RC04506SS-22A">22a </A>
Anderson PL. inventors; US Patent 4307113.
; Chem. Abstr. 1982, 96, 91666
<A NAME="RC04506SS-22B">22b </A> A similar result was found with baker’s yeast, see:
Blackie JA.
Turner NJ.
Wells AS.
Tetrahedron Lett.
1997,
38:
3043
<A NAME="RC04506SS-23">23 </A>
Muchnij JA.
Maleczka RE.
Chemoselective Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds with Polymethylhydrosiloxane
Presented at the 37th Organosilicon Symposium;
Philadelphia USA:
May 20-22, 2004.
p.Poster P-34
<A NAME="RC04506SS-24">24 </A>
This reaction also formed an unidentified minor byproduct.
<A NAME="RC04506SS-25A">25a </A>
Handbook of Organopalladium Chemistry for Organic Synthesis
Negishi E.
Wiley-Interscience;
New York:
2002.
<A NAME="RC04506SS-25B">25b </A>
Also see ref. 11.
<A NAME="RC04506SS-26">26 </A>
Askani R.
Taber DF. In
Comprehensive Organic Synthesis
Vol. 1:
Trost BM.
Fleming I.
Pergamon;
Oxford:
1991.
p.103-132
For reviews on nucleophilic addition to nitrones, see:
<A NAME="RC04506SS-27A">27a </A>
Lombardo M.
Trombini C.
Synthesis
2000,
759
<A NAME="RC04506SS-27B">27b </A>
Merino P.
Franco S.
Merchan FL.
Tejero T.
Synlett
2000,
442
For reviews on nitrones in 1,3-dipolar cycloadditions, see:
<A NAME="RC04506SS-27C">27c </A>
Wade PA. In
Comprehensive Organic Synthesis
Vol. 4:
Trost BM.
Fleming I.
Pergamon;
Oxford:
1991.
p.1111-1166
<A NAME="RC04506SS-27D">27d </A>
Padwa A. In Comprehensive Organic Synthesis
Vol. 4:
Trost BM.
Fleming I.
Pergamon;
Oxford:
1991.
p.1069-1106
<A NAME="RC04506SS-28">28 </A>
Bode JW.
Fox RM.
Baucom KD.
Angew. Chem. Int. Ed.
2006,
45:
1248
<A NAME="RC04506SS-29">29 </A>
Zschiesche R.
Reissig H.-U.
Tetrahedron Lett.
1988,
29:
1685
<A NAME="RC04506SS-30A">30a </A>
Bieber LW.
da Costa RC.
da Silva MF.
Tetrahedron Lett.
2000,
41:
4827
<A NAME="RC04506SS-30B">30b </A>
Rische T.
Eilbracht P.
Tetrahedron
1998,
54:
8441
<A NAME="RC04506SS-31">31 </A>
Chen L.
Li Z.
Li C.-J.
Synlett
2003,
732
<A NAME="RC04506SS-32A">32a </A>
Elmaaty TA.
Castle LW.
Org. Lett.
2005,
7:
5529
<A NAME="RC04506SS-32B">32b </A>
Yang D.
Fokas D.
Li J.
Yu L.
Baldino CM.
Synthesis
2005,
47
<A NAME="RC04506SS-32C">32c </A>
Freeman AW.
Urvoy M.
Criswell ME.
J. Org. Chem.
2005,
70:
5014
<A NAME="RC04506SS-33A">33a </A>
Nishiyama Y.
Naitoh Y.
Sonoda N.
Synlett
2004,
886
<A NAME="RC04506SS-33B">33b </A>
Chandrasekhar S.
Narsihmulu C.
Jagadeshwar V.
Synlett
2002,
771
<A NAME="RC04506SS-33C">33c </A>
Cenini S.
Crotti C.
Pizzotti M.
Porta F.
J. Org. Chem.
1988,
53:
1243
<A NAME="RC04506SS-34A">34a </A>
Kim BH.
Han R.
Piao F.
Jun YM.
Baik W.
Lee BM.
Tetrahedron Lett.
2003,
44:
77
<A NAME="RC04506SS-34B">34b </A>
Watanabe Y.
Tsuji Y.
Kondo T.
Takeuchi R.
J. Org. Chem.
1984,
49:
4451
<A NAME="RC04506SS-35A">35a </A>
Kamal A.
Reddy KS.
Prasad BR.
Babu AH.
Ramana AV.
Tetrahedron Lett.
2004,
45:
6517
<A NAME="RC04506SS-35B">35b </A>
Pratap TV.
Baskaran S.
Tetrahedron Lett.
2001,
42:
1983
<A NAME="RC04506SS-35C">35c </A>
Hrvatin P.
Sykes AG.
Synlett
1997,
1069
<A NAME="RC04506SS-36">36 </A>
For this reason these two anhydrides were not tested with the other nitroarenes.
<A NAME="RC04506SS-37">37 </A>
Andrews MA.
Chang TC.-T.
Cheng C.-WF.
Organometallics
1985,
4:
268
<A NAME="RC04506SS-38">38 </A>
Hanzlik RP.
Org. Synth. Coll. Vol. VI
Wiley;
New York:
1988.
p.560
<A NAME="RC04506SS-39">39 </A>
Corey EJ.
Venkateswarlu A.
J. Am. Chem. Soc.
1972,
94:
6190
<A NAME="RC04506SS-40">40 </A>
Babasinian VS.
Org. Synth., Coll. Vol. II
Wiley;
New York:
1943.
p.466
<A NAME="RC04506SS-41">41 </A>
Kornblum N.
Powers JW.
J. Org. Chem.
1957,
22:
455
<A NAME="RC04506SS-42">42 </A>
Guanti G.
Banfi L.
Narisano E.
J. Org. Chem.
1992,
57:
1540
<A NAME="RC04506SS-43">43 </A>
Sasai H.
Watanabe S.
Suzuki T.
Shibasaki M.
Org. Synth., Coll. Vol. X
Wiley;
New York:
2004.
p.571
<A NAME="RC04506SS-44">44 </A>
In prior studies (ref. 17) we obtained lesser results with Pd(OAc)2 purchased from other suppliers.
<A NAME="RC04506SS-45">45 </A>
Binder D.
Habison G.
Noe CR.
Synthesis
1977,
255
<A NAME="RC04506SS-46">46 </A> 6-(Benzyloxy)hexan-1-ol was prepared from a known literature procedure:
Bouzide A.
Sauvé G.
Tetrahedron Lett.
1997,
38:
5945
<A NAME="RC04506SS-47">47 </A> Prepared via the general nitroaldol procedure described in:
Seebach D.
Beck AK.
Mukhopadhyay T.
Thomas E.
Helv. Chim. Acta
1982,
65:
1101
<A NAME="RC04506SS-48">48 </A> This procedure was based on a protocol previously published:
Walba DM.
Thurmes WN.
Haltiwanger RC.
J. Org. Chem.
1988,
53:
1046
<A NAME="RC04506SS-49">49 </A>
Ballini R.
Bartoli G.
Synthesis
1993,
965