4276-09-9Relevant articles and documents
A Spiroalkylation Method for the Stereoselective Construction of α-Quaternary Carbons and Its Application to the Total Synthesis of (R)-Puraquinonic Acid
Elmehriki, Adam A. H.,Gleason, James L.
supporting information, p. 9729 - 9733 (2019/12/02)
Cyclic α-quaternary carbon stereocenters were prepared from biselectrophillic substrates and an easily prepared chiral bicyclic sulfonyl lactam. This was achieved in two steps by spiroalkylation, employing biphasic reaction conditions with a phase-transfer catalyst, followed by reduction and alkylation with a series of alkyl halide electrophiles. The products of this method were isolated in good yields with with high levels of diastereoselectivity. This methodology was employed in the enantioselective total synthesis of (R)-puraquinonic acid (1) for a late-stage installation of the α-quaternary carbon stereocenter. This enabled the shortest synthesis of 1 to date, an eight-pot sequence providing an overall yield of 14%.
Total Enantioselective Synthesis of the Endophytic Fungal Polyketide Phomolide H and Its Structural Revision
McNulty, James,McLeod, David
supporting information, p. 29 - 33 (2017/01/14)
A total synthesis of the proposed structure of the natural polyketide-macrolactone phomolide H 2 has been achieved following a bidirectional strategy from l-tartaric acid. The originally assigned structure of phomolide H displayed discordant NMR spectroscopic data in comparison with synthetic 2. The synthetic strategy was extended to prepare diastereomers and epimeric methyl-ethers of the natural product, structural analysis of which revealed a match of the natural product with diastereomer 27. The structural revision of phomolide H from 2 to the methanol solvate of compound 27 is presented.
Design, Synthesis, Fungicidal Activity, and Unexpected Docking Model of the First Chiral Boscalid Analogues Containing Oxazolines
Li, Shengkun,Li, Dangdang,Xiao, Taifeng,Zhang, Shasha,Song, Zehua,Ma, Hongyu
, p. 8927 - 8934 (2016/12/07)
Chirality greatly influences the biological and pharmacological properties of a pesticide and will contribute to unnecessary environmental loading and undesired ecological impact. No structure and activity relationship (SAR) of enantiopure succinate dehydrogenase inhibitors (SDHIs) was documented during the structure optimization of boscalids. On the basis of commercial SDHIs, oxazoline natural products, and versatile oxazoline ligands in organic synthesis, the first effort was devoted to explore the chiral SDHIs and the preliminary mechanism thereof. Fine-tuning furnished chiral nicotinamides 4ag as a more promising fungicidal candidate against Rhizoctonia solani, Botrytis cinerea, and Sclerotinia sclerotiorum, with EC50 values of 0.58, 0.42, and 2.10 mg/L, respectively. In vivo bioassay and molecular docking were investigated to explore the potential in practical application and plausible novelty in action mechanism, respectively. The unexpected molecular docking model showed the different chiral effects on the binding site with the amino acid residues. This chiral nicotinamide also featured easy synthesis and cost-efficacy. It will provide a powerful complement to the commercial SDHI fungicides with the introduction of chirality.
