Intramolecular reaction

About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.

Intramolecular Pd-catalyzed carboetherification and carboamination. Influence of catalyst structure on reaction mechanism and product stereochemistry.

Abstract: The intramolecular Pd-catalyzed carboetherification of alkenes affords 2-indan-1-yltetrahydrofuran products in moderate to good yield with good to excellent levels of diastereoselectivity. The stereochemical outcome of these reactions is dependent on the structure of the Pd catalyst. Use of PCy(3) or P[(4-MeO)C(6)H(4)](3) as the ligand for Pd leads to syn-addition of the arene and the oxygen atom across the double bond, whereas use of (+/-)-BINAP or DPP-benzene affords products that result from anti-addition. The catalyst-induced change in stereochemistry is likely due to a change in reaction mechanism. Evidence is presented that suggests the syn-addition products derive from an unprecedented transannular alkene insertion of an 11-membered Pd(Ar)(OR) complex. In contrast, the anti-addition products appear to arise from Wacker-type anti-oxypalladation. Studies on analogous Pd-catalyzed intramolecular carboamination reactions, which afford 2-indan-1-ylpyrrolidines that result from syn-addition, are also described.

Diastereoselective synthesis of protected syn 1,3-diols by base-catalyzed intramolecular conjugate addition of hemiacetal-derived alkoxide nucleophiles

Abstract: Reaction of the illustrated unsaturated hydroxy esters (X=OMe, R 2 =H, Me) and amides (X=N(Me)OMe, R 2 =H, Me) with benzaldehyde and potassium alkoxide or amide bases is reported. The resulting benzylidene acetals are obtained in good yields (71-84%) and with hidh selectivity (>90:10). In addition to an exploration of the scope of the reaction, a mechanistic study, involving the use of deuterated benzaldehyde to ascertain the rate-determining step of the process, is described

Enantioselective intramolecular hydroamination catalyzed by lanthanide ate complexes coordinated by N-substituted (R)-1,1'-binaphthyl-2,2'-diamido ligands.

Abstract: Ytterbium and lutetium ionic complexes derived from enantiopure substituted (R)-binaphthylamine ligands, of the general formula [Li(THF)n][Ln[(R)-C20H12(NR)2]2], have been investigated for the hydroamination/cyclization of several aminopentenes and an aminohexene. Complexes with isopropyl or cyclohexyl substituents on nitrogen atoms were found to be efficient catalysts under mild conditions for the formation of N-containing heterocycles with enantiomeric excesses up to 78%.