Chiral dipole-stabilized anions: experiment and theory in benzylic and allylic systems. Stereoselective deprotonations, pyramidal inversions, and stereoselective alkylations of lithiated (tetrahydroisoquinolyl)oxazolines
α-Amino nitrile 2a was conveniently prepared in two individual steps from chiral hexafluorophosphate salt isoquinolinium (−)-8b including anodic cyanation as an efficient means to activate the sp3 C1–H bond of the THIQ nucleus. The lithiation of 2a was carried out in THF at −80 °C in the presence of LDA to produce a stable α-amino carbanion which was condensed on a large variety of alkyl halides. The
Identification of an Imine Reductase for Asymmetric Reduction of Bulky Dihydroisoquinolines
作者:Hao Li、Ping Tian、Jian-He Xu、Gao-Wei Zheng
DOI:10.1021/acs.orglett.7b01274
日期:2017.6.16
developed by simply optimizing the amount of cosolvent, and up to 15 g L–1 1-Me DHIQ was converted completely without a feeding strategy. Furthermore, the reaction proceeded well for a panel of dihydroisoquinolines, affording the corresponding tetrahydroisoquinolines (mostly in S-configuration) in good yields (up to 81%) and with moderate to excellent enantioselectivities (up to 99% ee).
鉴定出一种新的来自烟粉虱(Stack Stackerbrandtia nassauensis)(Sn IR)的亚胺还原酶,与其他报道的亚胺还原酶相比,该酶对1-甲基-3,4-二氢异喹啉(1-Me DHIQ)的催化效率提高了25到1400倍。随后,通过简单地优化助溶剂的量,开发了一种有效的Sn IR催化工艺,无需进料策略即可完全转化多达15 g L –1 1-Me DHIQ。此外,对于一组二氢异喹啉,反应进行得很好,以高收率(高达81%)和中等至优异的对映选择性(高达99%ee)提供了相应的四氢异喹啉(大部分呈S-构型)。
Chiral dipole-stabilized anions: experiment and theory in benzylic and allylic systems. Stereoselective deprotonations, pyramidal inversions, and stereoselective alkylations of lithiated (tetrahydroisoquinolyl)oxazolines
作者:Kathleen Rein、Marta Goicoechea-Pappas、Tarakeshwar V. Anklekar、Georgina C. Hart、Gregory A. Smith、Robert E. Gawley