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3,4-Dihydro-2H-9-thia-1,4a-diazafluorene (2b) was found to be an extremely effective catalyst, the reaction with which was faster than that with DMAP.

To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. γ-Selective allylic substitution reaction with Grignard reagents catalyzed by copper Nheterocyclic carbene complexes and its application to enantioselective synthesis

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A low-valent titanium generated in situ from Ti(O-i-Pr)(4), Me(3)SiCl, and Mg powder in THF reacted with aryl- and alkyl-sulfonamides of aryl and alkyl amines in a reductive N-S/S-O/S-C bond cleaving pathway to provide the corresponding amines and hydrocarbons (and thiols) derived from the sulfonyl moiety. The reagent could also cleave sulfonates to the corresponding alcohols.

[reaction: see text] A highly practical, general method for catalytic formation of substituted pyridines from a variety of unactivated nitriles and alpha,omega-diynes is given. The reactions which were catalyzed by 5 mol % of dppe/CoCl2-6H2O in the presence of Zn powder (10 mol %) could proceed at rt to approximately 50 degrees C with high functional compatibility and regioselectivity.

[reaction: see text] A 2-(2,6-diisopropylphenyl)iminomethylpyridine (1a)/CoCl(2).6H(2)O/Zn reagent has been developed as an effective instant catalyst for the intra- and intermolecular cyclotrimerization of alkynes to substituted benzenes, making the method extremely practical since the reagent, 1a/CoCl(2).6H(2)O/Zn, is inexpensive and easy to handle and the reaction is less sensitive to moisture and is reasonably general.

Treatment of N-(2- or 3-alkynyl)amino esters with a low-valent titanium reagent diisopropoxy(η2-propene)titanium (1), generated in situ by the reaction of Ti(O-i-Pr)4 and 2i-PrMgCl, resulted in an intramolecular nucleophilic acyl substitution (INAS) reaction to afford α-alkylidene-pyrrolidinones or -piperidinones. Thus, treatment of N-propargyl-anthranilates 5, -indole-2-carboxylates 10, or -pyrrole-2-carboxylates 13 with 1 gave 4-quinolones 7, [1,2-a]indoles, or [1,2-a]pyrroles, respectively. Similarly, N-alkynylated α- or β-amino esters 14 or 15 with 1 afforded N-heterocycles 18 or 19. In the reaction of N-(2- or 3-alkenyl)amino esters with 1, the resulting INAS product underwent intramolecular carbonyl addition (ICA) reaction to afford the N-heterocyclic compounds having a cyclopropanol moiety in good to excellent yields. Thus, the treatment of N-alkenyl-anthranilate 4a, -indole-2-carboxylates 8 and 9, or -pyrrole-2-carboxylates 11 and 12 with 1 gave the corresponding quinoline derivative 6a, [1,2-a]indoles, or [1,2-a]pyrroles, respectively. The optically active N-heterocyclic compounds 20 and 21 were obtained from N-alkenylated α- or β-amino esters 16 or 17. A highly efficient total synthesis of allopumiliotoxin alkaloid 267A has also been accomplished. Thus, the N-propargyl-2[(1-hydroxy-1-methoxycarbonyl)ethyl]pyrrolidine 24 (from l-proline in six steps) reacted with 1 to afford the corresponding indolidinone 25 in 67% yield, which has previously been converted to allopumiliotoxin 267A.