A Novel, Highly Selective, and General Methodology for the Synthesis of 1,5-Diene-Containing Oligoisoprenoids of All Possible Geometrical Combinations Exemplified by an Iterative and Convergent Synthesis of Coenzyme Q10
摘要:
GRAPHICSA truly general, versatile, and highly regio- and stereoselective methodology for the synthesis of terpenoids containing 1,5-diene units of E and/or Z geometry critically involves Pd-catalyzed homoallyl- and homopropargyl-alkenyl coupling and Zr-catalyzed carboalumination of alkynes. By using this methodology, coenzyme Q(10), (E,Z,E)-geranylgeranoll, and other natural or unnatural compounds have been synthesized efficiently.
Nitrosopurines En Route to Potently Cytotoxic Asmarines
作者:Kanny K. Wan、Kotaro Iwasaki、Jeffrey C. Umotoy、Dennis W. Wolan、Ryan A. Shenvi
DOI:10.1002/anie.201411493
日期:2015.2.16
A nitrosopurine ene reaction easily assembles the asmarine pharmacophore and transmits remote stereochemistry to the diazepine‐purine hetereocycle. This reaction generates potent cytotoxins which exceed the potency of asmarine A (1.2 μM IC50) and supersede the metabolites as useful leads for biological discovery.
New sesquiterpene backbones are accessible after biotransformation of presilphiperfolan-8 beta-ol synthase (BcBOT2), a fungal sesquiterpene synthase, with non-natural farnesyldiphosphates in which methyl groups are shifted by one position toward the diphosphate terminus. One of the macrocycles formed, a new germacrene A derivative, undergoes a Cope rearrangement to iso-beta-elemene. Three of the new terpenoids show olfactoric properties that range from an intense peppery note to a citrus, ozone-like, and fruity scent.
A novel non-metathetic behavior of Grubbs catalyst: Ruthenium-mediated intramolecular [3 + 2] cycloaddition of bis-1,3-dienes
A ruthenium-mediated intramolecular [3 + 2] cycloaddition of bis-1,3-dienes to give bicyclic products, which is a novel non-metathetic behavior of Grubbs catalyst, is reported. The formation of a ruthenium-olefin complex is proposed to be a key step for the success of the reaction. (C) 2012 Elsevier B.V. All rights reserved.
A versatile and selective route to difunctional trisubstituted (E)-alkene synthons via zirconium-catalyzed carboalumination of alkynes
作者:Cynthia L. Rand、David E. Van Horn、Mark W. Moore、Eiichi Negishi