Copper‐Catalyzed Azide–Ynamide Cyclization to Generate α‐Imino Copper Carbenes: Divergent and Enantioselective Access to Polycyclic N‐Heterocycles
作者:Xin Liu、Ze‐Shu Wang、Tong‐Yi Zhai、Chen Luo、Yi‐Ping Zhang、Yang‐Bo Chen、Chao Deng、Rai‐Shung Liu、Long‐Wu Ye
DOI:10.1002/anie.202007206
日期:2020.10.5
Here an efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is reported, representing the first generation of α‐imino copper carbenes from alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities
mL of toluene, Rh(acac)(CO)2 as the metal precursor, (S,R)-(N-Bn)Yanphos as the ligand, CO:H2 = 10:10 bar, S/C = 20, HSiEt3 (0.3 mmol), and BF3.Et2O (0.3 mmol) The configuration of all of the products was determined to be S, except for 4m; only the desired regioisomer was obtained as determined by NMR analysis. Scheme 4. Synthetic Transformations Addition/Correction
反应以 0.1 mmol 规模在 0.5 mL 甲苯中进行,Rh(acac)(CO)2 作为金属前体,(S,R)-(N-Bn)Yanphos 作为配体,CO:H2 = 10: 10 bar, S/C = 20, HSiEt3 (0.3 mmol), and BF3.Et2O (0.3 mmol) 通过NMR分析确定仅获得所需的区域异构体。方案 4. 合成变换加法/校正
Rhodium/Yanphos-Catalyzed Asymmetric Interrupted Intramolecular Hydroaminomethylation of <i>trans</i>-1,2-Disubstituted Alkenes
The first interruptedasymmetrichydroaminomethylation reaction was developed. The challenging trans-1,2-disubstituted olefins were employed as substrates, and a series of valuable chiral pyrrolidinones and pyrrolidines were obtained in high yields with high regioselectivities and excellent enantioselectivities. Several synthetic transformations were conducted, demonstrating the high synthetic utility
Lewis Acid-Mediated Unprecedented Ring-Opening Rearrangement of 2-Aryl-<i>N</i>-tosylazetidines to Enantiopure (<i>E</i>)-Allylamines
作者:Manas K. Ghorai、Amit Kumar、Kalpataru Das
DOI:10.1021/ol7023218
日期:2007.12.1
of 2-aryl-N-tosylazetidines in polar and coordinating solvents followed by an unprecedented rearrangement to substituted achiral and chiral (E)-allylamines (ee >99%) is reported. The methodology has been applied for the synthesis of gamma-unsaturated-beta-amino acids. A plausible mechanism for the rearrangement is also described.