Novel Palladium Catalytic Systems for Organic TransformationsTakahiro Nishimura, Sakae UemuraSynlett 201-216 (2004)DOI:
10.1055/s-2004-815412
AbstractThis article summarizes the results of our recent studies on palladium catalytic systems for the oxidation of alcohols and betaalkenes using molecular oxygen or air together with several successful attempts to make the system recyclable from the viewpoint of ‘green and sustainable chemistry’.5.0 Palladium(II)-Catalyzed Oxidation of Terminal Alkenes to Methyl Ketones Using Molecular OxygenPalladium-catalyzed oxidation of alkenes to methyl ketones has been developed in synthetic organic chemistry as well as in industrial processes using PdCl
2 and CuCl
2 or Cu
2Cl
2 as catalysts in acidic water under an oxygen atmosphere.
23,24 However, this catalytic system is highly corrosive because of its acidic conditions and may cause the formation of chlorinated by-products in some cases. To overcome such drawbacks, halide-free catalytic systems have also been widely investigated.
25On the other hand, Mimoun and co-workers have reported that a Pd(II)-OOH species undergoes an oxygen transfer to terminal alkenes via peroxypalladation to afford methyl ketones as shown in
Scheme 12.
26
Scheme 12An example of the palladium-catalyzed oxidation of cyclopentene to cyclopentanone in ethanol using molecular oxygen as the sole reoxidant was reported by Takehira and co-workers in 1985.
9a They also proposed the formation of a Pd(II)-OOH species from palladium, ethanol, and oxygen.
9a,27In the course of our studies on the aerobic oxidation of alcohols described in previous sections, we proposed the in situ formation of a Pd(II)-OOH species as well as H
2O
2. This assumption prompted us to check whether this Pd(OAc)
2/pyridine/O
2 catalytic system is applicable to the oxidation of terminal alkenes based on
Scheme 12.
28 In fact, the treatment of 1-dodecene in toluene (5 mL) and 2-propanol (5 mL) in the presence of 5 mol% Pd(OAc)
2 and 20 mol% pyridine at 60°C for 6 hours under an oxygen atmosphere afforded the expected 2-dodecanone (70% GLC yield,
Scheme 13). Other simple terminal alkenes were converted to the corresponding methyl ketones in good yields under the same conditions. Interestingly, 10-undecen-1-ol was mainly transformed to 11-hydroxy-2-undecanone in 71% yield showing that a terminal double bond was oxidized much faster than a hydroxyl group. It is noteworthy that this oxidation system was applicable only to terminal alkenes, and not to internal ones.
Scheme 13A plausible reaction pathway for this oxidation using Pd(OAc)
2/pyridine/2-propanol/O
2 catalytic system is shown in
Scheme 14, where two catalytic cycles operate. One cycle is the oxidation of 2-propanol (cycle A) to give acetone and a Pd(II)-H species, the latter of which is transformed to a Pd(II)-OOH species by the reaction with oxygen. The Pd(II)-OOH species reacts with an alcohol to give an alkoxypalladium(II) species as well as H
2O
2.
9 This Pd(II)-OOH species also reacts with alkenes via peroxypalladation (
Scheme 12) in another catalytic cycle (cycle B) to produce methyl ketones and a Pd(II)-OH species which reacts with H
2O
2 to reproduce the Pd(II)-OOH species.
Scheme 14References[9a] Strucul G. Ros R. Michelin RA. Inorg. Chem. 21, 495 (1982)
(See Below)[9b] Takehira K. Hayakawa T. Orita H. Chem. Lett. 1835 (1985)
[9c] Hosokawa T. Murahashi S.-I. Acc. Chem. Res. 23, 49 (1990)
(See Below)For recent reviews see:[23a] Tsuji J. Palladium Reagents and Catalysis Wiley; New York: 1995. p.19-30
[23b] Jira R. In Applied Homogeneous Catalysis with Organometallic Compounds Cornils B. Herrmann WA. VCH; New York: 1996. p.374-393
[23c] Monflier E. Mortreux A. In Aqueous-Phase Organometallic Catalysis Cornils B. Herrmann WA. Wiley-VCH; New York: 1998. p.513-518
[23d] Takacs JM. Jiang XT. Curr. Org. Chem. 2003, 7: 369
Recent examples of Wacker oxidation of higher alkenes see:[24a] Smith AB. Cho YS. Friestad GK. Tetrahedron Lett. 39, 8765 (1998)
(See Below)[24b] Mohammedi O. Chemat F. Brégeault J.-M. Eur. J. Org. Chem. 1998, 1901
[24c] Karakhanov E. Maximov A. Kirillov AJ. Mol. Catal. A: Chem. 2000, 157: 25
[24d] Yokota T. Sakakura A. Tani M. Sakaguchi S. Ishii Y. Tetrahedron Lett. 2002, 43: 8887
[24e] Choi K.-M. Mizugaki T. Ebitani K. Kaneda K. Chem. Lett. 2003, 32: 180
[25a] Bäckvall J.-E. Hopkins RB. Tetrahedron Lett. 1988, 29: 2885
[25b] Bäckvall J.-E. Hopkins RB. Grennberg H. Mader MM. Awasthi AK. J. Am. Chem. Soc. 1990, 112: 5160
[25c] Yokota T. Fujibayashi S. Nishiyama Y. Sakaguchi S. Ishii Y. J. Mol. Catal. A: Chem. 1996, 114: 113
[25d] Kishi A. Higashino T. Sakaguchi S. Ishii Y. Tetrahedron Lett. 2000, 41: 99
[25e] Monflier E. Blouet E. Barbaux Y. Mortreux A. Angew. Chem. Int. Ed., Engl. 1994, 33: 2100
[25f] Monflier E. Tilloy S. Fremy G. Barbaux Y. Mortreux A. Tetrahedron Lett. 1995, 36: 387
[25g] Monflier E. Tilloy S. Blouet E. Barbaux Y. Mortreux A. J. Mol. Catal. A: Chem. 1996, 109: 27
[25h] Hirao T. Higuchi M. Hatano B. Ikeda I. Tetrahedron Lett. 1995, 36: 5925
[25i] Higuchi M. Yamaguchi S. Hirao T. Synlett 1996, 1213
[25j] ten Brink G.-J. Arends IW. Papadogianakis G. Sheldon RA. Chem. Commun. 1998, 2359
[25k] ten Brink G.-J. Arends IW. Papadogianakis G. Sheldon RA. Appl. Catal. A 2000, 194-195: 435
[25l] Ito H. Kusukawa T. Fujita M. Chem. Lett. 2000, 598
[26a] Mimoun H. Charpentier R. Mitschler A. Fischer J. Weiss R. J. Am. Chem. Soc. 102, 1047 (1980)
(See Below)[26b] Roussel M. Mimoun H. J. Org. Chem. 45, 5387 (1980)
(See Below)[26c] Mimoun H. Angew. Chem. Int. Ed. Engl. 21, 734 (1982)
[27] Takehira K. Hayakawa T. Orita H. Shimizu M. J. Mol. Catal. 53, 15 (1989)
[28] Nishimura T. Kakiuchi N. Onoue T. Ohe K. Uemura S. J. Chem. Soc., Perkin Trans. 1, 1915-18 (2000) DOI:
10.1039/b001854f
(Free!)
[9a]Preparation and oxygen-transfer properties of novel palladium(II) and platinum(II) hydroperoxo and alkylperoxo complexesStrukul, Giorgio; Ros, Renzo; Michelin, Rino A.Inorganic Chemistry (1982), 21(2), 495-500 (1982)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/pd-pt-hydroperoxo-complexes.pdf)
AbstractMononuclear hydroperoxo and tert-butylperoxo complexes RML2OOR1 (L = 1/2 diphosphine or monophosphine; M = Pd, Pt; R = H, Me3C; R1 = activated alkyl) were prepared by condensation reactions of RML2OH with R1OOH. Whereas Me3COOH reacts in all the cases tested, with H2O2 the preparation reaction is sensitive to the nature of R. These compds. behave as typical O-transfer agents, reacting with PPh3, CO, NO, and PhCHO. trans-CF3Pt(PPh2Me)OOCMe3 oxidized terminal olefins to the corresponding Me ketones.
____ ___ __ _
[9c]New aspects of oxypalladation of alkenesHosokawa, Takahiro; Murahashi, ShunichiAccounts of Chemical Research 23(2), 49-54 (1990)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/alkene.oxypalladation.pdf)
Summary: A review with 54 refs. dealing with mechanistic and synthetic aspects of intramol. oxypalladation and acetalization of alkenes.
____ ___ __ _
[24a]Convenient Wacker oxidations with substoichiometric cupric acetateAmos B. Smith, III, Young Shin Cho and Gregory K. FriestadTetrahedron Letters 39(48), 8765-8768 (1998)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/wacker.o2.cupric.acetate.pdf)
DOI:
10.1016/S0040-4039(98)01992-3
AbstractA modification of the Wacker oxidation of terminal olefins to methyl ketones using substoichiometric amounts of Cu(OAc)2 as a redox shuttle reagent is described. The modified procedure is generally high yielding despite reduced levels of copper salt and convenient. Importantly, in a problematic case, the conditions suppressed acidic hydrolysis during oxidation of substrate (+)-5 containing an acetonide.
Has been mentioned in Post 108566 (missing)
(dormouse: "improvements in wacker rxn. -neocelsis", Novel Discourse)____ ___ __ _
[26a]Palladium(II) tert-butyl peroxide carboxylates. New reagents for the selective oxidation of terminal olefins to methyl ketones.Mimoun, Hubert; Charpentier, Robert; Mitschler, Andre; Fischer, Jean; Weiss, RaymondJournal of the American Chemical Society 102(3), 1047-54 (1980)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/wacker-pd-h2o2-2.pdf)
AbstractThe synthesis and characterization of new Pd(II) tert-Bu peroxide carboxylates with the general formula [RCO2PdOO-tert-Bu]4 (R = Me, CCl3, CF3, C5F11) are described. X-ray data gave the crystal and mol. structures of [Cl3CCO2PdOO-tert-Bu]4 (I). The 4 Pd atoms of I are coplanar and are located approx. at the corners of a square. Four trichloroacetate bridging anions are alternatively above and below this square. I are highly efficient reagents for the selective stoichiometric oxidation of terminal olefins to Me ketones at ambient temperature, and catalysts for the ketonization of terminal olefins by tert-Bu hydroperoxide. A mechanism involving a 5-membered pseudocyclic peroxymetalation of the coordinated olefin was suggested.
____ ___ __ _
[26b]Palladium-catalyzed oxidation of terminal olefins to methyl ketones by hydrogen peroxideRoussel, Michel; Mimoun, HubertJournal of Organic Chemistry (1980), 45(26), 5387-90 (1980)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/wacker-pd-h2o2-1.pdf)
AbstractPd(II) complexes are very efficient catalysts or the selective oxidation of terminal olefins RCH:CH2 (R = n-hexyl, n-octyl, n-decyl, AcOCH2) to RCOMe by H2O2. HOCH2CH:CH2 gave a mixture of HCO2H, AcOH, and EtCO2H. This reaction is best carried out in solvents such as tert-BuOH or AcOH, and requires a large excess of H2O2 with respect to the olefin in order to achieve a nearly complete conversion of the substrate without precipitation of metallic Pd. The general trend of this reaction suggested a mechanism very similar to that previously shown for the oxidation of terminal olefins by Pd(II) tert-Bu peroxide carboxylates, and involving a pseudocyclic hydroperoxypalladation of the coordinated olefin.