60249-53-8Relevant academic research and scientific papers
On the configurational stability of chiral heteroatom-substituted [D 1]Methylpalladium complexes as intermediates of stille and suzuki-miyaura cross-coupling reactions
Malova Krizkova, Petra,Hammerschmidt, Friedrich
, p. 5143 - 5148 (2013/11/06)
Enantiomerically pure (S)-tributylstannyl[D1]methanol and (R)- and (S)-tributylstannyl[D1]methyl benzoates were Stille-coupled with bromobenzene and benzoyl chloride in 1,4-dioxane and toluene using [(Ph 3P)4Pd] or [(Ph3P)2PdCl2] either alone or in combination with CuCN as cocatalyst at temperatures up to 80 °C. The products were found to be enantiomerically pure. (R)- and (S)-N-(tributylstannyl[D1]methyl)phthalimides gave enantiomerically pure products with benzoyl chloride, but with bromobenzene protected phenyl[D1]methylamines gave products of only 52-69 % ee depending on the solvent used. Tributyl(thio[D1]methyl)stannanes could not be Stille-coupled with benzoyl chloride or with bromobenzene. Similarly, dimethyl phenyl[D1]methylboronate underwent a Suzuki-Miyaura coupling with bromobenzene to give phenyl[D1]methylsilane with 99 % ee. All couplings followed a retentive course and, except in one case, the intermediate [XCHDPdLn] complexes were found to be microscopically configurationally stable. Stille coupling of enantiomerically pure tributylstannyl[D1]methanol, its benzoate, and the N-(tributylstannyl[D1]methyl)phthalimide with bromobenzene and benzoyl chloride furnished products containing a chiral XCHD group. Overall net retention of configuration was found in all cases.
Enantioselective borodeuteride reduction of aldimines catalyzed by cobalt complexes: Preparation of optically active deuterated primary amines
Miyazaki, Daichi,Nomura, Kohei,Yamashita, Tatsuya,Iwakura, Izumi,Ikeno, Taketo,Yamada, Tohru
, p. 3555 - 3558 (2007/10/03)
[Equation presented] The enantioselective borodeuteride reduction catalyzed by optically active β-ketoiminato cobalt complexes was applied to N-(di(o-tolyl)phosphinyl)-aldimines to afford the corresponding optically active deuterated primary amines in hig
Transformation of Arylmethylamines into α-Aminophosphonic Acids via Metalated Phosphoramidates: Rearrangement of Partly Configurationally Stable N-Phosphorylated α-Aminocarbanions
Hammerschmidt, Friedrich,Hanbauer, Martin
, p. 6121 - 6131 (2007/10/03)
N-Benzyl phosphoramidate was protected at nitrogen with a TMS, p-toluenesulfonyl, Boc, lithium carboxylate, or diethoxyphosphinyl group and metalated with s-BuLi or LDA at -78 °C at the benzylic carbon. For the latter three protecting groups, the intermediate α-amino(phenylmethyl)-lithiums isomerized to N-protected α-aminophosphonates (phosphoramidate-aminophosphonate rearrangement). (R)-N-[1-2H1]Phenylmethyl phosphoramidate in combination with Boc or (EtO)2P-(O) was used to demonstrate that metalation occurs with a high primary kinetic isotope effect (kH/kD 13-50) and migration of the diethoxyphosphinyl group with retention of configuration at carbon. Furthermore, the short-lived carbanion lithium pairs are partly configurationally stable as the aminophosphonates formed with the two protecting groups have enantiomeric excesses of 79 and 24%, respectively. When homochiral lithium amides derived from (R)-N-isopropyl-1-phenylethylamine and (R,R)-N,N-di(1-phenylethyl)amine were used to induce a phosphoramidate-aminophosphonate rearrangement, chiral nonracemic α-aminophosphonates were formed (ee 26-35%). Three racemic aminophosphonates were deprotected with hot 6 M HCl and purified by ion-exchange chromatography on Dowex 50W,H+ to exemplify the transformation of phenyl-, p-tolyl-, and (1′-naphthyl)methylamine into aminophosphonic acids via lithiated phosphoramidates.
