Kinetic resolution of racemic 2,2′-bis(trifluoromethane-sulfonyloxy)-1,1′-binaphthalene by chiral dimethylaluminum complexes and an achiral Pd catalyst, as well as by achiral dimethylaluminum reagents in the presence of a chiral Pd catalyst

Synthesis and Characterization of Intramolecularly Stabilized Chiral Dimethylindium Alkoxides and their Use as Cross Coupling ReagentsProfessor Joachim Strähle zum 65. Geburtstag gewidmet

“…[Me 2 In{µ-O(CH 2 ) 2 NMe 2 }] 2 (1) [13] as well as [Me 2 In{µ-OCH 2 CH(Me)NMe 2 }] 2 (2) [7] were prepared using the reported procedures. The palladium catalysts formed in situ by interacting palladium(II) acetate with either (R,S)-or (S)-bis(diphenylphosphino)-1,1Ј-binaphthalene (binap) were used as previously described [14]. Elemental analyses were performed on a Perkin-Elmer 240 C elemental analyzer.…”

“…Mp: 111°C. C 14 (R,S)-1,1Ј-(C 10 H 6 ) 2 -2-CO 2 CH 3 -2Ј-OSO 2 CF 3 [(R,S)-8]. The racemic ester was prepared from the racemic 2,2Ј-bis(trifluorometansulfonyloxy)-1,1Ј-binaphthalene [15], Pd(OAc) 2 , and 1,3-bis(diphenylphosphino)propane in 45 % yield in analogy to the preparation of the R-isomer [16].…”

Palladium catalyzed cross‐methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents

“…Upon replacement of one of the alkyl groups by a chelating ligand such as the (3-dimethylamino)propyl group [2,3], the dialkylaluminum complexes, so formed, are safe enough for handling under standard laboratory conditions. [ propyl]dimethylaluminum (1 a) was successfully utilized in the alkylation of various carbonyl compounds [4], as well as in palladium-and nickelcatalyzed cross-methylation of carbocyclic aryl halides and triflates [5][6][7][8][9]. However, in all but one case [6] this mononuclear methylating reagent failed to couple with heterocyclic substrates, probably because of its tendency to form highly stable adducts v i a the lone pairs of the heteroatoms [10].…”

“…[ propyl]dimethylaluminum (1 a) was successfully utilized in the alkylation of various carbonyl compounds [4], as well as in palladium-and nickelcatalyzed cross-methylation of carbocyclic aryl halides and triflates [5][6][7][8][9]. However, in all but one case [6] this mononuclear methylating reagent failed to couple with heterocyclic substrates, probably because of its tendency to form highly stable adducts v i a the lone pairs of the heteroatoms [10]. In this paper we report a way to overcome this shortcoming by replacing of 1 a by either the analogous gallium or the indium reagent (1b or 1c) [11].…”

Palladium Catalyzed Cross‐Methylation of Bromoheterocycles with Intramolecularly Stabilized Dimethyl Indium Reagents.

“…Upon replacement of one of the alkyl groups by a chelating ligand such as the (3-dimethylamino)propyl group [2,3], the dialkylaluminum complexes, so formed, are safe enough for handling under standard laboratory conditions. [(3-Dimethylamino)propyl]dimethylaluminum (1 a) was successfully utilized in the alkylation of various carbonyl compounds [4], as well as in palladium-and nickelcatalyzed cross-methylation of carbocyclic aryl halides and triflates [5][6][7][8][9]. However, in all but one case [6] this mononuclear methylating reagent failed to couple with heterocyclic substrates, probably because of its tendency to form highly stable adducts v i a the lone pairs of the heteroatoms [10].…”