Palladium catalysed pronucleophile addition to unactivated carbon–carbon multiple bonds

Yamamoto, Yoshinori; Radhakrishnan, Ukkiramapandian

doi:10.1039/a806581k

Cited by 225 publications

(56 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1][2][3][4] Among them, reactions that involve carbopalladation of allenes, which generate p-allylpalladium intermediates, followed by internal nucleophilic attack by a heteroatom or carbanion, are particularly valuable (Fig. 1).…”

mentioning

confidence: 99%

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Inamoto

Yamamoto

Ohsawa

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

Palladium-catalyzed annulation processes have proved to be extremely useful and powerful methods for the construction of diverse carbocycles and heterocycles.1-4) Among them, reactions that involve carbopalladation of allenes, which generate p-allylpalladium intermediates, followed by internal nucleophilic attack by a heteroatom or carbanion, are particularly valuable (Fig. 1). [5][6][7][8][9][10][11][12][13][14][15][16] Larock et al. have extensively investigated the palladium-catalyzed annulation reactions of carbon-atom-substituted allenes using functionally substituted aryl iodides or vinyl halides. [13][14][15][16] Yields were generally high and most of the reactions are both stereo-and regioselective; however, the reactions sometimes afforded mixtures of regioisomers, especially in six-membered-ring formation. 13,14) Meanwhile, only one example of an annulation reaction of heteroatom-substituted allenes has been reported, and in that case the presence of the heteroatom on allenes and its electronic effect dominated the regioselectivity (Fig. 2).17) With the aim of regioselectively synthesizing highly functionalized heterocycles, we employed heteroatomsubstituted allenes for palladium-catalyzed annulation. We found that various aryl iodides and bromides reacted smoothly and that one regioisomer was produced exclusively both in five-and six-membered-ring formations. Furthermore, in the course of our extensive studies on the synthetic application of annulated products, we also found that alkyl metal reagents reacted unexpectedly in SN2Ј fashion at the exomethylene carbon of the annulated products obtained by the palladium-catalyzed annulation reaction. Several metal reagents were reactive and an alkyl moiety could be introduced by this process.Synthesis of Heteroatom-Substituted Allenes Heteroatom-substituted allenes (1, 2) used for the palladium-catalyzed annulation reaction were prepared according to the protocol as follows (Fig. 3). [18][19][20] O-Substituted allene 1 was obtained via O-benzylation of propargyl alcohol followed by treatment withN-Substituted allene 2 was synthesized using commercially available N-Boc-N-tosylamide as a starting material. Mitsunobu reaction of N-Boc-N-tosylamide with propargyl alcohol, followed by removal of Boc using 3 N HCl in MeOH under reflux, afforded N-propargyl-N-tosylamide 3 in 91% yield. Benzylation of amide 3 and subsequent isomerization produced the desired allene 2.Palladium-Catalyzed Annulation Reactions of Allenes Using Various Aryl Iodides/Bromides (Table 1) With heteroatom-substituted allenes 1 and 2 in hand, we first examined the annulation reaction of them using various aryl iodides.A variety of reaction conditions have been examined, and the use of an inorganic base, K 2 CO 3 , and a polar solvent, DMF, has proved to be effective for this process. All reactions were highly regioselective and only one regioisomer was observed.In annulation of allene 1 using N-tosyl-2-iodoaniline as an aryl halide, the reaction proceeded smoothly at 80°C in the * To whom cor...

show abstract

mentioning

confidence: 99%

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Inamoto

Yamamoto

Ohsawa

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

show abstract

“…Addition of nucleophiles to activated carbon-carbon multiple bonds by -coordination to Pd(II) is a commonly process in Pdpromoted organic reactions [4]. Addition of amines to conjugated enynes was first reported by Yamamoto et al to occur using [( 3 -C 3 H 5 )PdCl] 2 as precursor, in the presence of dppf ligand and acetic acid (Scheme 2, eq.…”

Section: A Hydroamination Reactions Of C=c Bondsmentioning

confidence: 99%

Palladium-Catalyzed Heterofunctionalization of C-H, C=C and C≡ C Bonds

Adrio¹,

Hii²

2011

COC

View full text Add to dashboard Cite

The heterofunctionalisation of C-H, C=C and C C bonds is an important type of transformation that converts readily accessible precursors to valuable intermediates in organic synthesis, particularly when the heteroatom = N or O. The progress in this area of homogeneous catalysis by palladium is described in the current review, covering the period between 2005-early 2010. Asymmetric reactions remain a key challenge in this area, which is highlighted.

show abstract

“…Selective activation of multiple carbon-carbon bonds and/or benzene ring is of great importance in chemical industry [1,2]. Among of which, hydrogenation of cinnamaldehyde is a popularly reported model reaction for the selective activation of α, β-unsaturated carbonyl compounds [3,4], selective hydrogenation of phenol to cyclohexanone is an important step in the production of Nylon 6, Nylon 66, and polyamide resins [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Selective hydrogenation of C C bond over N-doped reduced graphene oxides supported Pd catalyst

Nie

Miao

et al. 2016

Applied Catalysis B: Environmental

158

View full text Add to dashboard Cite

Palladium catalysed pronucleophile addition to unactivated carbon–carbon multiple bonds

Cited by 225 publications

References 32 publications

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Palladium-Catalyzed Heterofunctionalization of C-H, C=C and C≡ C Bonds

Selective hydrogenation of C C bond over N-doped reduced graphene oxides supported Pd catalyst

Contact Info

Product

Resources

About

Palladium catalysed pronucleophile addition to unactivated carbon–carbon multiple bonds

Cited by 225 publications

References 32 publications

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Highly Regioselective Palladium-Catalyzed Annulation Reactions of Heteroatom-Substituted Allenes for Synthesis of Condensed Heterocycles

Palladium-Catalyzed Heterofunctionalization of C-H, C=C and C&#x2261; C Bonds

Selective hydrogenation of C C bond over N-doped reduced graphene oxides supported Pd catalyst

Contact Info

Product

Resources

About

Palladium-Catalyzed Heterofunctionalization of C-H, C=C and C≡ C Bonds