2121-67-7Relevant articles and documents
Chiral interactions in azobenzene dimers: A combined experimental and theoretical study
Painelli, Anna,Terenziani, Francesca,Angiolini, Luigi,Benelli, Tiziana,Giorgini, Loris
, p. 6053 - 6063 (2005)
To investigate interchromophore interactions in azobenzene polymers, we have undertaken a thorough spectroscopic analysis of the azodye [(5)-3-pivaloyloxy-1-(4'-nitro-4-azobenzene)pyrrolidine] by modeling the repeating unit of poly[(S)3-methacryloyloxy-1-(4'-nitro-4-azobenzene) pyrrolidine) and its dimeric derivative whose synthesis is presented here. The analysis of the electronic and Raman spectra of the azodye in several solvents is based on a previously proposed model for polar chromophores in solution. Electronic and CD spectra of the dimeric unit are collected and analyzed within the framework of a new model. On the basis of the information collect ed from the spectroscopic analysis of the solvated dye, this model accounts for interchromophore interactions in the dimer. The large CD signal measured for the dimer (amounting to about a third of the signal measured for the polymer) suggests the presence of important chiral interactions in the dimeric unit, and is modeled in terms of a right-handed relative orientation of the two chromophores.
The Catalytic Alkylative Desymmetrization of Anhydrides in a Formal Synthesis of Ionomycin
Oberg, Kevin M.,Cochran, Brian M.,Cook, Matthew J.,Rovis, Tomislav
supporting information, p. 4343 - 4350 (2018/06/08)
The catalytic desymmetrization of anhydrides with zinc reagents provides access to deoxypolypropionate and polypropionate synthons. A synthesis of ionomycin was pursued in which three of the four fragments were assembled using this methodology. Two of the strategies (enol silane/oxocarbenium coupling and reductive cyclization) were not successful at installing the C23 stereocenter, but this stereochemical issue was overcome through a reduction/S N 2 approach. In addition to the synthesis of a protected diastereomer of ionomycin, the synthesis of a C17-C32 fragment constitutes a formal total synthesis.
Toward a total synthesis of okilactomycin. 1. A direct, enantiocontrolled route to the western sector
Paquette, Leo A.,Boulet, Serge L.
, p. 888 - 894 (2007/10/03)
A synthesis of the western half of the macrocyclic ring framework of the antitumor antibiotic okilactomycin is described. The strategy employed rests on an efficient synthesis of meso-2,4-dimethylglutaric anhydride and ensuing resolution via reaction with (S)-(-)-α-methylbenzylamine, diborane reduction, and selective crystallization. Following acid-catalyzed cyclization to (2S,4R)-2,4-dimethyl-δ-valerolactone, an acyclic stereocontrol strategy was adopted to achieve chain lengthening with appropriate incorporation of functionality. The sensitive aldehyde 2 was further homologated to β-keto ester 17 in a model reaction sequence performed to simulate its ultimate projected coupling to 3.
