Catalytically Asymmetric Pd/Norbornene Catalysis: Enantioselective Synthesis of (+)-Rhazinal, (+)-Rhazinilam, and (+)-Kopsiyunnanine C1–3

Abstract

A catalytically asymmetric palladium/norbornene-catalyzed reaction is reported, where α-aryl tetrahydroquinoline derived phosphoramidite L15 is found to be the optimum ligand. Taking advantage of this transformation, the concise and unified enantioselective syntheses of (+)-rhazinal, (+)-rhazinilam, and (+)-kopsiyunnanine C1, C2, and C3 are realized.

Chiral Catalysts for Pd0‐Catalyzed Enantioselective C−H Activation

“…Two years after their report on the first enantioselective Catellani reaction (see Scheme 10), [42] Gu and co‐workers established efficient conditions for the atropo‐enantioselective synthesis of axially chiral biaryls 102 by a Catellani‐type reaction between a naphthyl bromide ( 99 ), boronic acid ( 100 ), and chloromethyl ether ( 101 ; Scheme 43). [108] In contrast to the previous Catellani reaction where carbopalladation was enantiodetermining, the enantiodetermining step of the current reaction is either the transmetalation between the naphthylpalladium intermediate and boronic acid 100 or the subsequent reductive elimination.…”

Mechanistic Study of Copper-Catalyzed C-H Hydroxylation/C-S Coupling by ESI-HR MS and DFT Calculations

“…The application of electrospray ionization high resolution mass spectrometry (ESI-HR MS) provides key intermediates with mass information. Density functional theory (DFT) can compute the reaction pathways with respect to different energy profiles for intermediate species and transition states [ 21 , 22 ]. We reported on the highly efficient Cu-catalyzed C-H hydroxylation/C-S coupling ( Scheme 1 ) [ 23 , 24 ].…”

Alkylating Reagents Employed in Catellani‐Type Reactions

“…3) Although several examples involving the use of catalytic amounts of mediator have been reported, there is still much room for improvement to realize general mediator catalysis, and novel powerful catalytic mediators are highly desirable. 4) To date, quite limited examples of catalytically asymmetric Catellani‐type ortho ‐alkylation have been reported . Future efforts can be invested in this direction.…”

“…4) To date, quite limited examples of catalytically asymmetric Catellani-type ortho-alkylation have been reported. [60] Futureefforts can be invested in this direction.…”