Enantioselective hydrophosphonylation of N - benzyl imines, isatin derived ketimines and isatins catalyzed by in-situ generated Ti(IV) macrocyclic salen complexes
作者:Mohd Nazish、Ajay Jakhar、Noor-ul H. Khan、Shailesh Verma、Rukhsana I. Kureshy、Sayed H.R. Abdi、Hari C. Bajaj
DOI:10.1016/j.apcata.2015.12.037
日期:2016.4
benzylimines, whereas for ketiminesdiphenylphosphite (IIb) gave best results with very good yield (up to 88%) and ee (up to 99%). The Ti(IV) complex was recoverable and recyclable with retention of its catalytic performance at gram scale level. To understand the reaction mechanism NMR studies have been carried out using benzylimine as a model substrate and dimethyl phosphite as a nucleophile.
Construction of Vicinal Tetrasubstituted Stereogenic Centers<i>via</i>a Mannich-Type Organocatalyzed Addition of Δ<sup>2</sup>-Pyrrolin-4-ones to Isatin Imines
Mannich‐type addition to isatin‐derived ketimines to furnish the non‐racemic oxindole‐Δ2‐pyrrolin‐4‐one adducts, stereoselectively (up to 96% ee, dr≥15:1). The oxindole–pyrrolone products feature vicinaltetrasubstituted carbon stereocenters. The developed protocol has a broad substrate scope and tolerates diverse substituents at position C‐5 in 4‐pyrrolones and at positions N‐1 and C‐5/7 in isatin imines
First example of quinine-squaramide catalyzed enantioselective addition of diphenyl phosphite to ketimines derived from isatins
作者:Jimil George、B. Sridhar、B. V. Subba Reddy
DOI:10.1039/c3ob42026d
日期:——
A highlyenantioselective addition of diphenyl phosphite to ketimines derived from isatins has been achieved using a bifunctional organocatalyst, quinine-derived squaramide catalyst. This method works efficiently with several ketimines to produce the corresponding 3-amino-2-oxoindolin-3-yl-phosphonates in excellent yields with high enantioselectivity (up to 98% ee).
Highly Enantioselective Addition of Enals to Isatin-Derived Ketimines Catalyzed by N-Heterocyclic Carbenes: Synthesis of Spirocyclic γ-Lactams
作者:Hui Lv、Bhoopendra Tiwari、Junming Mo、Chong Xing、Yonggui Robin Chi
DOI:10.1021/ol302475g
日期:2012.11.2
An N-heterocycliccarbene (NHC)-catalyzed annulation reaction of isatin N-Boc ketimines and enals is developed for the synthesis of spirocyclic oxindole-γ-lactams bearing one quaternary chiral center in good yields and excellent stereoselectivities (up to >20:1 dr and 99% ee).
Enantioselective construction of 3-substituted 3-amino-2-oxindoles containing an <i>N</i>,<i>N</i>-ketal skeleton <i>via</i> organocatalyzed aza-addition of isatin imines
作者:Chen Zhang、Xinye Shang、Yuyu Cheng、Fushuai Li、Hanhui Zhao、Pengfei Li、Wenjun Li
DOI:10.1039/c9ob01870k
日期:——
The first example of organocatalytic chemo-, regio- and enantioselective aza-Mannich reactions of triazoles and arylamines, respectively, with isatin-derived imines has been achieved.