DOI: 10.1002/chem.201304300
Full Paper
& C H Activation
Palladium-Catalyzed C H Activation and Intermolecular Annulation with Allenes Xiao-Feng Xia,[a, b] Yu-Qi Wang,[a] Lu-Lu Zhang,[a] Xian-Rong Song,[a] Xue-Yuan Liu,[a] and Yong-Min Liang*[a] Abstract: A new and efficient PdII-catalyzed intermolecular annulation of N-benzoylsulfonamide with allenes for the synthesis of 3,4-dihydroisoquinolin-1(2H)-ones is reported. This C H functionalization is compatible with ambient air and moisture, and it can be applied to terminal or internal al-
Introduction The carbometalation reaction of allenes provides efficient access to highly versatile and reactive p-allyl metal species, which can undergo Tsuji–Trost-type substitutions in the presence of external nucleophiles to obtain the allylic functionalized products.[1] Pioneered by Larock et al., Pd0-catalyzed carbometalation reaction of allenes with halogenated starting materials has proven to be a valuable method for the synthesis of a variety of heterocycles (Scheme 1 a).[2] However, these methods necessitate the use of halogenated substrates, which require extra synthetic operations thus limiting their availability. Thus, realizing PdII-catalyzed C H bond activation for the carbometalation of allenes was particularly important. Palladium-catalyzed C H bond functionalization for hydroarylation of C C multiple bonds has emerged as a powerful, distinct, and atom-economical method for the construction of C C bonds from cheap and readily available starting materials in organic synthesis.[3] Despite the fact that great progress has been made on the hydroarylation of alkenes and alkynes through C H bond functionalization in recent years under palladium catalysis, such reports on the reactions of allenes are rare; In particular, examples that utilize the directing group-induced metal-catalyzed hydroarylation of allenes to construct the C C bonds are very limit-
[a] Dr. X.-F. Xia, Y.-Q. Wang, Dr. L.-L. Zhang, Dr. X.-R. Song, Dr. X.-Y. Liu, Prof. Dr. Y.-M. Liang State Key Laboratory of Applied Organic Chemistry Lanzhou University, Lanzhou 730000 (P.R. China) Fax: (+ 86) 931-8912582 E-mail: [email protected] [b] Dr. X.-F. Xia School of Chemical and Material Engineering Jiangnan University, Wuxi, 214122 (P.R. China) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201304300. Chem. Eur. J. 2014, 20, 5087 – 5091
lenes with different synthetically attractive functional groups. Control experiments and a kinetic isotope effect study are conducted and a plausible mechanism is proposed.
Table 1. Optimization of the reaction conditions.[a]
Entry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22[c] 23[d] 24[e]
Oxidant [equiv] [Cu(OAc)2]·H2O Ag2CO3 K2S2O8 PhI(OAc)2 Ag2CO3 + BQ Ag2O AgOAc 1 atm O2 [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O
2.0 2.0 2.0 2.0 1.0 + 0.5 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
Base Solvent (2.0 equiv)
T Yield [8C] [%][b]
CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc Cs2CO3 NaOAc KOAc K3PO4 K2CO3 CsF CsOAc CsOAc CsOAc
100 100 100 100 100 100 100 100 100 80 80 100 100 100 100 100 100 100 100 100 100 100 100 100
toluene toluene toluene toluene toluene toluene toluene toluene xylene DCE CH3CN DMF Chloro-benzene O-xylene dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane
46 17 N.D. decomposed 27 31 31
Full Paper
& C H Activation
Palladium-Catalyzed C H Activation and Intermolecular Annulation with Allenes Xiao-Feng Xia,[a, b] Yu-Qi Wang,[a] Lu-Lu Zhang,[a] Xian-Rong Song,[a] Xue-Yuan Liu,[a] and Yong-Min Liang*[a] Abstract: A new and efficient PdII-catalyzed intermolecular annulation of N-benzoylsulfonamide with allenes for the synthesis of 3,4-dihydroisoquinolin-1(2H)-ones is reported. This C H functionalization is compatible with ambient air and moisture, and it can be applied to terminal or internal al-
Introduction The carbometalation reaction of allenes provides efficient access to highly versatile and reactive p-allyl metal species, which can undergo Tsuji–Trost-type substitutions in the presence of external nucleophiles to obtain the allylic functionalized products.[1] Pioneered by Larock et al., Pd0-catalyzed carbometalation reaction of allenes with halogenated starting materials has proven to be a valuable method for the synthesis of a variety of heterocycles (Scheme 1 a).[2] However, these methods necessitate the use of halogenated substrates, which require extra synthetic operations thus limiting their availability. Thus, realizing PdII-catalyzed C H bond activation for the carbometalation of allenes was particularly important. Palladium-catalyzed C H bond functionalization for hydroarylation of C C multiple bonds has emerged as a powerful, distinct, and atom-economical method for the construction of C C bonds from cheap and readily available starting materials in organic synthesis.[3] Despite the fact that great progress has been made on the hydroarylation of alkenes and alkynes through C H bond functionalization in recent years under palladium catalysis, such reports on the reactions of allenes are rare; In particular, examples that utilize the directing group-induced metal-catalyzed hydroarylation of allenes to construct the C C bonds are very limit-
[a] Dr. X.-F. Xia, Y.-Q. Wang, Dr. L.-L. Zhang, Dr. X.-R. Song, Dr. X.-Y. Liu, Prof. Dr. Y.-M. Liang State Key Laboratory of Applied Organic Chemistry Lanzhou University, Lanzhou 730000 (P.R. China) Fax: (+ 86) 931-8912582 E-mail: [email protected] [b] Dr. X.-F. Xia School of Chemical and Material Engineering Jiangnan University, Wuxi, 214122 (P.R. China) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201304300. Chem. Eur. J. 2014, 20, 5087 – 5091
lenes with different synthetically attractive functional groups. Control experiments and a kinetic isotope effect study are conducted and a plausible mechanism is proposed.
Table 1. Optimization of the reaction conditions.[a]
Entry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22[c] 23[d] 24[e]
Oxidant [equiv] [Cu(OAc)2]·H2O Ag2CO3 K2S2O8 PhI(OAc)2 Ag2CO3 + BQ Ag2O AgOAc 1 atm O2 [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O [Cu(OAc)2]·H2O
2.0 2.0 2.0 2.0 1.0 + 0.5 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
Base Solvent (2.0 equiv)
T Yield [8C] [%][b]
CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc CsOAc Cs2CO3 NaOAc KOAc K3PO4 K2CO3 CsF CsOAc CsOAc CsOAc
100 100 100 100 100 100 100 100 100 80 80 100 100 100 100 100 100 100 100 100 100 100 100 100
toluene toluene toluene toluene toluene toluene toluene toluene xylene DCE CH3CN DMF Chloro-benzene O-xylene dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane dioxane
46 17 N.D. decomposed 27 31 31
