Asymmetric Ni(II)/Cr(II)-Mediated Coupling Reaction:  Catalytic Process

Abstract

[reaction: see text] A novel C3V-symmetric scaffold, trindane 7, has been efficiently synthesized from 1,3,5-tris(bromomethyl)-2,4,6-tris(chloromethyl)benzene (1) in six steps with 47% overall yield. The control of all-syn stereochemistry in the tribenzylation step has been achieved by blocking one side of the trindane ring as metal carbonyl complexes. The potential utility of trindane 7 as a receptor skeleton has been examined with a urea derivative 12 toward several anionic guests.

Artificial Receptors for the Recognition of Phosphorylated Molecules

“…386 This scaffold allowed for the preorganization of all three urea arms on the same side of the receptor. The binding properties were analyzed via 1 H NMR spectroscopy in DMSO- d 6 using various TBA anion salts.…”

Catalytic Enantioselective Addition of Allylic Organometallic Reagents to Aldehydes and Ketones

“…Recently, Kishi also applied sulfonamide ligands such as 54 in these additions. 100,101 The enantioselectivities however, still remain modest.…”

Total Synthesis of (−)-Chromodorolide B

“…12 A variety of standard conditions were examined for the Nozaki-Hiyama-Kishi coupling of iodide 19 with aldehyde 20 ; 18 however, only low yields (<20%) and modest diastereoselectivities (3:1) were observed. In contrast, in the presence of ( R )-sulfonamide ligand 21 introduced by Kishi, 19 allylic alcohol 22 was obtained in 66% yield as a single alcohol epimer. Saponification of the ester and subsequent esterification with N -hydroxyphthalimide provided crystalline ester 23 in 69% yield, whose structure was confirmed by single-crystal X-ray analysis.…”