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A facile and efficient approach has been established for the synthesis of benzoindole and naphthofuran derivatives via the metal-free cyclization reaction of nitroolefins with naphthylamines/naphthols. Various substituted benzoindoles and naphthofurans are obtained in good to excellent yields. Moreover, the ability to recycle the carbonaceous material makes this method quite cost-effective and environmentally benign compared to traditional acid-catalyzed methods. Theoretical studies indicated that the reaction between naphthylamine and nitroolefin catalyzed by this solid acid was thermodynamically controlled at 60 °C, resulting in the formation of the benzoindoles.

A highly enantioselective group 5 metal amide catalyst system is reported for the hydroaminoalkylation of secondary amines to give chiral amines in good yields with excellent ee values (up to 93%) by loading of 5% precatalyst.

A one-pot three-component reaction for the synthesis of 4- thiazolidinone derivatives has been established by reacting readily available and inexpensive starting materials of amines, aldehydes and thioglycolic acid using Y(OTf)3 (5 mol%) as catalyst in tetrahydrofuran. This method is very efficient due to low catalyst loading and mild reaction conditions and provides an efficient and promising synthetic strategy for the construction of the thiazolidinone skeleton. [ABSTRACT FROM AUTHOR]

Abstract: Five group 4 metal complexes (1)2Zr(NMe2)2 (5), (2)2Ti(NMe2)2 (6), (2)2Zr(NMe2)2 (7), (3)2Zr (8) and (4)2Ti(NMe2)2 (9) have been readily prepared from the reaction between M(NMe2)4 (M=Ti, Zr) and chiral binaphthyldiamine-based ligands, (R)-2,2′-bis(diphenylthiophosphoramino)-1,1′-binaphthyl (1H2), (R)-5,5′,6,6′,7,7′,8,8′-octahydro-2,2′-bis(diphenylthiophosphoramino)-1,1′-binaphthyl (2H2), (R)-5,5′,6,6′,7,7′,8,8′-octahydro-2,2′-bis(methanesulphonylamino)-1,1′-binaphthyl (3H2), and C 1-symmetric ligand, (R)-2-(mesitylenesulphonylamino)-2′-(dimethylamino)-1,1′-binaphthyl (4H). All the complexes have been characterized by various spectroscopic techniques, elemental analyses and X-ray diffraction analyses. The zirconium amides are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in good yields with moderate ee (enantiomeric excess) values. [Copyright &y& Elsevier]

Abstract: A new series of titanium(IV) and zirconium(IV) amides have been prepared from the reaction between M(NMe2)4 (M=Ti, Zr) and C 2-symmetric ligands, (R)-2,2′-bis(pyridin-2-ylmethylamino)-6,6′-dimethyl-1,1′-biphenyl (2H2), (R)-2,2′-bis(pyrrol-2-ylmethyleneamino)-6,6′-dimethyl-1,1′-biphenyl (3H2), (R)-2,2′-bis(diphenylphosphinoylamino)-6,6′-dimethyl-1,1′-biphenyl (4H2), (R)-2,2′-bis(methanesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (5H2), (R)-2,2′-bis(p-toluenesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (6H2), and C 1-symmetric ligands, (R)-2-(diphenylthiophosphoramino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (7H) and (R)-2-(pyridin-2-ylamino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (8H), which are derived from (R)-2,2′-diamino-6,6′-dimethyl-1,1′-biphenyl. Treatment of M(NMe2)4 with 1 equiv. of N4-ligand, 2H2 or 3H2 gives, after recrystallization from an n-hexane solution, the chiral zirconium amides (2)Zr(NMe2)2 (9), (3)Zr(NMe2)2 (11), and titanium amide (3)Ti(NMe2)2 (10), respectively, in good yields. Reaction of Zr(NMe2)4 with 1 equiv of diphenylphosphoramide 4H2 affords the chiral zirconium amide (4)Zr(NMe2)2 (12) in 85% yield. Under similar reaction conditions, treatment of Ti(NMe2)4 with 1 equiv. of sulphonylamide ligand, 5H2 or 6H2 gives, after recrystallization from a toluene solution, the chiral titanium amides (5)Ti(NMe2)2·0.5C7H8 (13·0.5C7H8) and (6)Ti(NMe2)2 (15), respectively, in good yields, while reaction of Zr(NMe2)4 with 1 equiv. of 5H2 or 6H2 gives the bis-ligated complexes, (5)2Zr (14) and (6)2Zr (16). Treatment of M(NMe2)4 with 2 equiv. of diphenylthiophosphoramide ligand 7H or N3-ligand 8H gives, after recrystallization from a benzene solution, the bis-ligated chiral zirconium amides (7)2Zr(NMe2)2 (17) and (8)2Zr(NMe2)2 (19), and bis-ligated chiral titanium amide (8)2Ti(NMe2)2 (18), respectively, in good yields. All new compounds have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of complexes 10, 12, 13, and 17–19 have further been confirmed by X-ray diffraction analyses. The zirconium amides are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in good to excellent yields with moderate ee values, while the titanium amides are not. [Copyright &y& Elsevier]

A concise and efficient three-component domino strategy promoted by acetic acid has been established for the synthesis of novel spirocycloalkane fused pyrazolo[3,4- b pyridine-dicarbonitrile derivatives in 73–90% yields. The domino reaction is easy to perform by mixing 1 H -pyrazol-5-amines or isoxazol-5-amine, 2-arylidenemalononitriles, and cyclic ketones in the presence of acetic acid at 80 °C in 2–4 h. The present procedure shows attractive properties including inexpensive and easy starting materials, simple one-pot operation, large substrate scope, highly isolated yields, and easy purification process. This chemistry provides a promising synthetic strategy to construction of N -containing spirocycle skeleton with stereogenic centers. Image 1 • A reaction for synthesis of spirocycloalkane fused pyrazolo[3,4- b pyridines has been established. • The reaction can be finished within 2–4 h with water as sole byproduct. • This chemistry provides a strategy to construction of N -containing spirocycles with stereogenic center. [ABSTRACT FROM AUTHOR]