Imines diene catalyzed arylation

Rhodium Diene-Catalyzed Arylation of Imines Hayashi has shown that the asymmetric synthesis of diarylmethylamines could be realized with high enantio control by the rhodium catalyzed arylboronic acid addition to N tosyl imines [119]. Ihe rhodium catalyst bears the C2 symmetrical bicyclo 2.2.1]heptadicne ligand 54. 

In the Diels-Alder reaction between Danishefsky s diene and N-aryl imines derived from o-hydroxyaniline catalyzed by Ih, Akiyama observed substantial increases in chemical yield and enantioselectivty by the addition of stoichiometric amounts of acetic acid (Scheme 5.14) [27]. The authors concede that the role of the protic acid is unclear. 

The protic acid and Lewis acid-catalyzed [4 + 2] cycloaddition reactions of electron-rich alkenes with imines derived from anilines and aryl aldehydes constitute an extensively explored class of 2-azadienes capable of providing the products of a formaJ Diels-Alder reaction (equation 9).i5.27.i77 a useful extension of these studies and in efforts to increase the rate of the Att participation of simple 2-aza-1,3-buta-dienes in [4 + 2] cycloaddition reactions, Mariano and coworkers have examined the Lewis acid-catalyzed intermolecular reactions of (l ,3 )-l-phenyl-2-aza-l,3-pentadiene with electron-rich dienophiles, including enol ethers. Reductive work-up of the cycloaddition reactions provided the pro-... 

Organolanthanide-catalyzed intermolecular hydrophosphination is a more facile process than intermolecular hydroamination. The reaction of alkynes, dienes, and activated alkenes with diphenylphosphine was achieved utilizing the ytterbium imine complex 9 (Fig. 8) as catalyst [185-188]. Unsymmetric internal alkynes react regioselectively, presumably due to an aryl-directing effect (48) [186]. 

A variety of secondary cyclic and acyclic amines may also couple with vinyl bromides catalyzed by Pd/BINAP or L13.117 This serves as a useful alternative for enamine synthesis. The vinylation of primary amines gives enamines which immediately tataumerize to the corresponding imine. Competition experiments reveal that vinyl bromides react in preference to aryl bromides. Vinyl chlorides are also aminated to give enamines or amino dienes118 as well. These may then serve as useful nucleophiles or dienes for Diels-Alder reactions. 

A variety of electrophiles are employed for carbonyl alkenylation and arylation that proceed through transmetalation from silicon to transition metal catalysts. For example, addition of alkenylsilanes and aryl(trimethoxy)si lanes to aldehydes is catalyzed by copper/DTBM-SEGPHOS, which mediates transmetalation from silicon to copper to give a wide variety of chiral alcohols with high degree of % ee (Scheme 3-144). The enantioselective alkenylation of imines using 2-(hydroxylmethyl)phenyl-substituted propen-2-ylsilane is catalyzed by a rhodium/chiral diene complex. ... 

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