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Turning the Nitrogen Atoms of an Ar2P−CH2−N−N−CH2−PAr2 Motif into Uniquely Configured Stereocenters: A Novel Diphosphane Design for Asymmetric Catalysis

“…Figure retrieves the construction principle of the above‐mentioned diphosphane DIOP ( 2 , Figure ) in many newer diphosphanes from asymmetric catalysis studies: This is based on recognizing these compounds 5 , 6 , 7 , 8 , 9 , 10 11 , 12 , 13 , 14 , 15 , and 16 consistently as “2,3‐disubstituted‐1,4‐di‐unsubstituted‐1,4‐diphosphanes”.…”

Synthesis and enantiomeric recognition ability of 22-crown-6 ethers derived from rosin acid and BINOL

“…For example, the Diels-Alder products of rosin acid with maleic acid anhydride or fumarate acid 2 or 3 (Scheme 2) contain three functional groups in their cyclic chiral structures, 10 and their reduction products 4 or 5 (Scheme 2) possessing three hydroxyl groups served as the linkage part of the host molecular in the present crown ether synthesis. The introduction of a 2,2 0 -dihydroxy-1,1 0 -binaphthyl (BINOL) unit on these crown ethers may result in some interesting features: (i) the formation of dual chiral architectures with different rosin structures to control the shape and the cavity of the crown, for observing special selectivity to different guests; (ii) providing supplementary rigid steric and chiral barriers, which may allow different enantioselective interactions with chiral guest enantiomers; and (iii) to facilitate photophysical studies involving intramolecular UV-vis spectroscopy, because of the presence of the photoactive 1,1 0 -binaphthyl chromophore.…”

“…9 Recently, some of its derivatives have been applied in catalytic asymmetric reactions. 10 In our previous work, we have reported using maleopimaric acid in the separations of D/L-amino acids by capillary electrophoresis. 11 As part of our ongoing programme to develop crown ethers based on multiple cyclic chiral natural products for enantiomeric separation and to investigate the enantiodiscrimination of crown ethers with two significant different diastereotopic faces, we herein report a short-step synthesis of four enantiomerically pure crown ethers containing hydroxyl end groups, using maleopimaric acid, fumaropimaric acid and BINOL as starting materials, and their enantiodiscriminating abilities towards protonated primary amines and amino acid methyl ester salts by using the UV-vis titration method.…”

Natural compounds in the synthesis of chiral organophosphorous ligands

“…73 First syntheses of chiral organophosphorus ligands from diterpenoids were described in the studies. 74,75 The authors of the cited studies used the known adducts of levopimaric acid (194a) with maleic anhydride (compound 195) and diethyl fumarate (compound 196) as well as the adduct of the benzyl ether of levopimarol (194b) with diethyl fumarate (compound 197).…”