Reaction of benzyl (2,2-diphenyl-4,5-hexadienyl)carbamate (4) with a catalytic 1:1 mixture of Au[P(t-Bu)2(o-biphenyl)]Cl (2) and AgOTf (5 mol %) in dioxane at 25 degrees C for 45 min led to isolation of benzyl 4,4-diphenyl-2-vinylpyrrolidine-1-carboxylate (5) in 95% yield. The Au(I)-catalyzed intramolecular hydroamination of N-allenyl carbamates tolerated substitution at the alkyl and allenyl carbon atoms and was effective for the formation of piperidine derivatives. gamma-Hydroxy and delta-hydroxy allenes also underwent Au-catalyzed intramolecular hydroalkoxylation within minutes at room temperature to form the corresponding oxygen heterocycles in good yield with high exo-selectivity. 2-Allenyl indoles underwent Au-catalyzed intramolecular hydroarylation within minutes at room temperature to form 4-vinyl tetrahydrocarbazoles in good yield. Au-catalyzed cyclization of N-allenyl carbamates, allenyl alcohols, and 2-allenyl indoles that possessed an axially chiral allenyl moiety occurred with transfer of chirality from the allenyl moiety to the newly formed stereogenic tetrahedral carbon atom.

Reaction of 2,3-pentadienyl benzoate and benzyl carbamate with a catalytic 1:1 mixture of (NHC) AuCl and AgOTf in dioxane at 23 °C for 5 h led to isolation of (E)-4-(benzyloxycarbonylamino)-2-pentenyl benzoate in 84% yield as a single regio-and diastereomer. Gold(I)-catalyzed hydroamination was effective for a number of N-unsubstituted carbamates and a range of substituted allenes.Allylic amines are components of many naturally occurring and biologically active molecules and are versatile building blocks for the synthesis of complex nitrogen-containing molecules. As a result, considerable effort has been directed toward the development of general and selective methods for the synthesis of allylic amines. 1,2 The transition metal-catalyzed addition of the N-H bond of an amine or carboxamide derivative across the C=C bond of an allene represents an attractive and atom economical approach to the synthesis of allylic amines. 3 However, whereas general and efficient methods for the intramolecular hydroamination of allenes have been developed, 4,5 the intermolecular hydroamination of allenes remains problematic and no methods are availavble that effectively employ ammonia or ammonia equivalents as nucleophiles. 6,7 Here we describe a general, regio-and stereoselective gold(I)-catalyzed protocol for the intermolecular hydroamination of allenes that employs Nunsubstituted carbamates as ammonia surrogates.We have developed an effective protocol for the intramolecular hydroamination of N-γ-and δ-allenyl carbamates catalyzed by a mixture of the gold phosphine complex (1)AuCl [1 = PtBu 2 o-biphenyl] 5 and AgOTf and a protocol for the intermolecular hydroalkoxylation of allenes with alcohols catalyzed by a mixture of the gold (NHC) complex (2)AuCl [2 = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidine] and AgOTf (Scheme 1). 8,9 We therefore targeted (1) AuCl and (2) AuCl as precatalysts for the intermolecular hydroamination of allenes with Nunsubstituted carbamates. In an initial experiment, reaction of 3-methyl-1,2-butadiene (3) and benzyl carbamate catalyzed by a 1:1 mixture of (1)AuCl and AgOTf in dioxane at 23 °C for rwidenho@chem.duke.edu. Supporting Information Available: Experimental procedures and scans of NMR spectra for N-allylic carbamates (PDF). This material is available free of charge via the Internet at

[reaction: see text] Reaction of enyne 1 with catecholborane catalyzed by a 1:1 mixture of [Rh(COD)(2)](+)SbF(6)(-) and (S)-BINAP (5 mol %) followed by Pd-catalyzed arylation with p-IC(6)H(4)CF(3) gave benzylidenecyclopentane 5 in 65% yield with 88% ee. Rhodium-catalyzed asymmetric cyclization/hydroboration followed either by Pd-catalyzed arylation or by oxidation was applied to the synthesis of a number of chiral, nonracemic carbocycles and heterocycles.

Ring closure reactions O 0130Highly Active Au(II) Catalyst for the Intramolecular exo-Hydrofunctionalization of Allenes with Carbon, Nitrogen, and Oxygen Nucleophiles. -A 1:1 mixture of gold complex AUR and AgOTf is a highly active and selective catalyst for the intramolecular exo-hydroamination of N-allenyl carbamates and for the exo-hydroarylation of 2-allenyl indoles. A 1:1 mixture of AUR and AgOTos is very efficient for the exo-hydroalkoxylation of allenyl alcohols. For all three types of optically active allenes a transfer of chirality to the newly formed stereogenic carbon atom is observed with selective formation of the (E)-alkene (to be continued). -(ZHANG, Z.; LIU, C.; KINDER, R. E.; HAN, X.; QIAN, H.; WIDENHOEFER*, R. A.; J. Am. Chem. Soc. 128 (2006) 28, 9066-9073; P.M. Gross Chem. Lab., Duke Univ., Durham, NC 27708, USA; Eng.) -Klein 48-036

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Carbamic acid derivatives P 0480 Intermolecular Hydroamination of Allenes with N-Unsubstituted Carbamates Catalyzed by a Gold(I) N-Heterocyclic CarbeneComplex. -The reaction is general for mono-1,3-and 1,1-disubstituted, tri-and tetrasubstituted allenes. Reaction of enantioenriched (XI) results in formation of a racemic product. -(KINDER, R. E.; ZHANG, Z.; WIDENHOEFER*, R. A.; Org. Lett. 10 (2008) 14, 3157-3159; French Family Sci. Cent., Duke Univ., Durham, NC 27708, USA; Eng.) -R. Steudel 48-052

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.