Preparation of Enantiopure Chiral Amino-[D<sub>1</sub>]methyllithium Compounds and Determination of Their Micro- and Macroscopic Configurational Stabilities
作者:Dagmar C. Kapeller、Friedrich Hammerschmidt
DOI:10.1002/chem.200802668
日期:2009.6.2
Enantiopure aminomethyllithiums, such as depicted, the smallest of their kind, have been prepared and tested for their micro‐ and macroscopic configurationalstabilities, which are delicately influenced by R1 and R2. The species with R1=R2=Bn is macroscopically configurationally stable below −95 °C.
越小越好:对映纯氨基甲基锂,如图所示,是同类中最小的,已经制备并测试了它们的微观和宏观构型稳定性,这些稳定性受到 R 1和 R 2 的微妙影响。R 1 =R 2 =Bn 的物质在-95 °C 以下宏观构型稳定。
On the Preparation and Determination of Configurational Stability of Chiral Thio- and Bromo[D<sub>1</sub>]methyllithiums
作者:Anna Wieczorek、Friedrich Hammerschmidt
DOI:10.1021/jo301441g
日期:2012.11.16
Thio- and bromo[D1]methyllithiums (ee 99%) were generated from the respective stannanes by tin–lithium exchange at temperatures ranging from 0 to −95 °C. Thio[D1]methyllithiums 6 were found to be microscopically configurationally labile on the time scale of the thiophosphate-α-mercaptophosphonate rearrangement even at −95 °C. Thio[D1]methyllithiums 13a and 13b underwent a thia-[2,3]-Wittig rearrangement
硫代和溴代 [D 1 ] 甲基锂(ee 99%)是通过锡-锂交换在 0 到 -95 °C 的温度下从各自的锡烷中生成的。发现硫代[D 1 ] 甲基锂6在硫代磷酸盐-α-巯基膦酸盐重排的时间尺度上即使在-95°C 下在微观上也不稳定。Thio[D 1 ] 甲基锂13a和13b经历了低至 -95 °C 的 thia-[2,3]-Wittig 重排,而13b仅低至 -50 °C。前者在-95°C以下微观构型稳定,后者在-50°C下完全消旋。手性溴[D 1] 甲基锂在 -78 °C 时化学性质不稳定,但在其加入苯甲醛和苯乙酮的时间尺度上在微观结构上是稳定的。
Configurational Stability of Oxymethyllithiums as Intermediates in Intramolecular Rearrangements
作者:Dagmar C. Kapeller、Lothar Brecker、Friedrich Hammerschmidt
DOI:10.1002/chem.200701054
日期:2007.11.26
were tested for their microscopic configurational stability in intramolecular isomerizations, such as the silyl- and germyl-[1,2]-retro-Brook and the sigmatropic[2,3]-Wittig rearrangement. The influence of temperature, solvent, and migrating group on the stability of the intermediate carbanions was studied. Furthermore, the stereochemical course of these rearrangements was elucidated, resulting in highly
On the Configurational Stability of Chiral Heteroatom-Substituted [D<sub>1</sub>]Methylpalladium Complexes as Intermediates of Stille and Suzuki-Miyaura Cross-Coupling Reactions
作者:Petra Malova Krizkova、Friedrich Hammerschmidt
DOI:10.1002/ejoc.201300439
日期:2013.8
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
Preparation and Configurational Stability of Chiral Chloro-[D<sub>1</sub>]methyllithiums of 98% Enantiomeric Excess
作者:Dagmar C. Kapeller、Friedrich Hammerschmidt
DOI:10.1021/ja0779708
日期:2008.2.1
Enantiopure stannyl-[D1]methanol was converted to chloro-[D1]methylstannane under complete inversion of configuration using Ph3P/N-chlorosuccinimide in THF. It was transmetalated to stereospecifically give chloro-[D1]methyllithium (ee up to 98%). Its microscopic configurationalstability was tested by performing tin-lithium exchange in the presence of benzaldehyde as the electrophile under various