Stereoselective deconjugation of macrocyclic α,β-unsaturated esters by sequential amidation and olefin transposition: application to enantioselective phase-transfer catalysis

Abstract

The stereoselective synthesis of chiral macrocycles bearing two aliphatic amide functional groups is reported.

Circularly polarized luminescence from Tb(iii) interacting with chiral polyether macrocycles

“…Recently, the direct synthesis of a new family of highly functionalized chiral polyether macrocycles of type 1, made in only two steps from cyclic ethers, was reported. [46][47][48] These molecules find applications in a variety of fields 49,50 from analytical 51 and supramolecular 52 sciences to catalysis, 53 luminescence [54][55][56][57] and photophysics. [58][59][60] Herein, in a new development, we report that the complex formed by ligand 1a (X = O, Fig.…”

Recent Advances in Carbon‐Nitrogen/Carbon‐Oxygen Bond Formation Under Transition‐Metal‐Free Conditions

“…Later in 2019, Lacour and co-workers developed a similar protocol for the amidation of macrocyclic esters using TBD and KOtBu. [79] Another organic base (DBU) was also recognized as a useful promoter in amidation reactions by Kim and co-workers, using trichloroethyl esters and amines as the coupling partners. [80] In 2017, the Jamieson group described a 2,2,2-trifluoroethanol (TFE)-catalyzed amidation protocol of methyl esters (154) via active intermediates (155) (Scheme 30).…”

From reactive carbenes to chiral polyether macrocycles in two steps – synthesis and applications made easy?

“…In this case, it is necessary to decouple (i) the amidation realized by addition of aliphatic amines in the presence of TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) from (ii) the olen transposition step that is still performed under strongly basic conditions. 24 Various linear and a-branched primary amines can be introduced and afford chiral aliphatic macrocycles in moderate to good yields. Of interest, it is possible to introduce enantiopure amines that lead to mixtures of diastereoisomers separable by simple ash chromatography and then obtain diastereomerically (and enantiomerically) pure compounds.…”

“…water), 21a the coordination of cations like Na + within the cavity of the polyether macrocycles was evidenced by X-ray crystallography during the preparation of the compounds. 24 This ability to complex alkali metal salts and render them soluble in non-polar solvents can be put to use in efficient phase transfer catalysis (PTC) protocols. In fact, using non-racemic crown ether macrocycles, it is possible to achieve enantioselective alkylation, 1,4-addition or oxidation.…”

“…7). 24 Knowing that macrocycles of type 1 can bind cations, the addition of complementary anion binding sites was further considered. The ditopic receptor formation was realized in a single synthetic step using amino-substituted derivative 1c.…”