133-04-0Relevant articles and documents
Synthesis of Lignans Based on a Borate-mediated One-pot Sequential Suzuki-Miyaura Coupling of Cyclic Boranes
Sato, Ko,Tanaka, Hiroshi
supporting information, p. 9422 - 9428 (2021/05/26)
Lignans are a group of polyphenolic phytochemicals that possess a large spectrum of chemical structures and biological activities. Here the syntheses of lignans – anwulignan, burseran, dehydroxycubebin, ruburisandrin B, and sesamin – are achieved based on a borate-mediated one-pot sequential Suzuki-Miyaura coupling of cis- and trans-fused bicyclic boranes, which were prepared by diastereoselective cyclic hydroboration of exo-cyclic diene with cyclopentyl- and thexylboranes, respectively. A one-pot sequential Suzuki-Miyaura coupling of each cyclic borate with various aryl bromides initiated by activation of the cyclic borane with the carbon nucleophile provided 2,3-dibenzylbutane derivatives with different aromatic substituents. Finally, the syntheses of naturally occurring lignans were accomplished in several steps from the products of Suzuki-Miyaura coupling.
Chromatography-free “two-pots” asymmetric total synthesis of (+)-sesamin and (+)-aschantin
Hajra, Saumen,Garai, Sujay,Sen, Biswajit
, (2020/09/02)
A gram-scale chromatography-free asymmetric total synthesis of both homo- and heterobiaryl furofuran lignans containing at least one methylenedioxy phenyl unit such as (+)-sesamin and (+)-aschantin is accomplished in “two-pots” from easily accessible enantiopure lactone involving four steps in high overall yields. Steps- and pot economy are the key advantages of the protocol. Additionally, the bromo-functionality of the intermediates is useful for late stage functionalization.
Metal Triflates for the Production of Aromatics from Lignin
Deuss, Peter J.,Lahive, Ciaran W.,Lancefield, Christopher S.,Westwood, Nicholas J.,Kamer, Paul C. J.,Barta, Katalin,de Vries, Johannes G.
, p. 2974 - 2981 (2016/11/02)
The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology relies on the use of catalytic amounts of easy-to-handle metal triflates (M(OTf)x). Initially, we evaluated the reactivity of a broad range of metal triflates using simple lignin model compounds. More advanced lignin model compounds were also used to study the reactivity of different lignin linkages. The product aromatic monomers were either phenolic C2-acetals obtained by stabilization of the aldehyde cleavage products by reaction with ethylene glycol or methyl aromatics obtained by catalytic decarbonylation. Notably, when the method was ultimately tested on lignin, especially Fe(OTf)3 proved very effective and the phenolic C2-acetal products were obtained in an excellent, 19.3±3.2 wt % yield.
