171860-91-6Relevant articles and documents
Carbamoyl Fluoride-Enabled Enantioselective Ni-Catalyzed Carbocarbamoylation of Unactivated Alkenes
Li, Yue,Luan, Yu-Xin,Qi, Shao-Long,Wang, Rong-Hua,Ye, Mengchun,Zhang, Feng-Ping
, p. 19844 - 19849 (2021/01/01)
A carbamoyl fluoride-enabled enantioselective Ni-catalyzed carbocarbamoylation of unactivated alkenes was developed, providing a broad range of chiral γ-lactams bearing an all-carbon quaternary center in 45-96% yield and 38-97% ee.
Pyrone Diels-Alder Routes to Indolines and Hydroindolines: Syntheses of Gracilamine, Mesembrine, and Δ7-Mesembrenone
Gan, Pei,Smith, Myles W.,Braffman, Nathaniel R.,Snyder, Scott A.
, p. 3625 - 3630 (2016/03/23)
Although the Diels-Alder reaction has long been utilized for the preparation of numerous heterocycles, opportunities to extend its power remain. Herein, we detail a simple, modular, and robust approach that combines various amines regioselectively with 4,6-dichloropyrone to create substrates which, under appropriate conditions, can directly deliver varied indolines and hydroindolines through [4+2] cycloadditions with substitution patterns difficult to access otherwise. As an initial demonstration of the power of the strategy, several different natural products have been obtained either formally or by direct total synthesis, with efforts toward one of these - the complex amaryllidaceae alkaloid gracilamine - affording the shortest route to date in terms of linear step count. Pyrone-technics: A simple, robust, and readily modifiable strategy involving [4+2]/retro-[4+2]/hydrolysis cascade sequences generates a range of indolines and hydroindolines from 4,6-dichloropyrone and appropriate amines. A 10 step synthesis was achieved of a ketone previously accessed in 15 steps, thereby accomplishing the shortest formal total synthesis of the alkaloid gracilamine. Teoc=2-(trimethylsilyl)ethoxycarbonyl.
Ligand-controlled regiodivergent nickel-catalyzed annulation of pyridones
Donets, Pavel A.,Cramer, Nicolai
supporting information, p. 633 - 637 (2015/03/04)
The 1,6-annulated 2-pyridone motif is found in many biologically active compounds and its close relation to the indolizidine and quinolizidine alkaloid core makes it an attractive building block. A nickel-catalyzed C-H functionalization of 2-pyridones and subsequent cyclization affords 1,6-annulated 2-pyridones by selective intramolecular olefin hydroarylation. The switch between the exo- and endocyclization modes is controlled by two complementary sets of ligands. Irrespective of the ring size, the regioselectivity during the cyclization is under full catalyst control. Simple cyclooctadiene promotes an exo-selective cyclization, whereas a bulky N-heterocyclic carbene ligand results in an endoselective mode. The method was further applied in the synthesis of the lupin alkaloid cytisine.
