- The asymmetric total synthesis of cinbotolide: A revision of the original structure
-
The structure 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1) was assigned to a metabolite of Botrytis cinerea, but the spectra of several synthetic analogues had significant differences from that of 1. Examination of the constituents of a B. cinerea mutant that overproduces polyketides gave sufficient quantities of 1, now named cinbotolide, for chemical transformations. These led to a revised γ-butyrolactone structure for the metabolite. This structure has been confirmed by an asymmetric total synthesis, which also established its absolute configuration.
- Botubol, Jos Manuel,Durn-Pena, Mara Jess,Macas-Snchez, Antonio J.,Hanson, James R,Collado, Isidro G.,Hernndez-Galn, Rosario
-
-
Read Online
- Convergent total synthesis of corallocin A
-
The first total synthesis of corallocin A is described herein. The Suzuki coupling reaction as a key step proceeded with high stereoselectivity and in good yield. Robust transformations, including Vilsmeier-Haack formylation and Wittig reaction, allowed for effective access to corallocin A.
- Mashiko, Tomoya,Nakazato, Yuta,Katsumura, Yuta,Kasamatsu, Akihiko,Adachi, Shinya,Kamo, Shogo,Matsuzawa, Akinobu,Sugita, Kazuyuki
-
supporting information
p. 5127 - 5132
(2021/06/21)
-
- Expanded substrate scope and improved reactivity of ether-forming cross-coupling reactions of organotrifluoroborates and acetals
-
Mixed acetals and organotrifluoroborates undergo BF3· OEt2-promoted cross-couplings to give dialkyl ethers under simple, mild conditions. A survey of reaction partners identified a hydroxamate leaving group that improves the regioselectivity and product yield in the BF 3·OEt2-promoted coupling reaction of mixed acetals and potassium alkynyl-, alkenyl-, aryl- and heteroaryltrifluoroborates to access substituted dialkyl ethers. This leaving group enables the reaction to proceed rapidly under mild conditions (0 °C, 5-60 min) and permits reactions with electron-deficient potassium aryltrifluoroborates that are less reactive with other acetal substrates. A study of the reaction mechanism and characterization of key intermediates by NMR spectroscopy and X-ray crystallography identified a role for the hydroxamate moiety as a reversible leaving group that serves to stabilize the key oxocarbenium intermediate and the need for a slight excess of organodifluoroborane to serve as a catalyst. A secondary role for the boron nucleophile as an activating ligand was also considered. These studies provide the basis for a general class of reagents that lead to dialkyl ethers by a simple, predictable cross-coupling reaction.
- Vo, Cam-Van T.,Mitchell, T. Andrew,Bode, Jeffrey W.
-
supporting information; experimental part
p. 14082 - 14089
(2011/10/12)
-
- FACILE FUNCTIONALIZATION OF THE ISOPROPYLIDENE TERMINUS OF ACYCLIC MONOTERPENES BY WAY OF BENZENESULFENYL CHLORIDE ADDITION
-
Highly site- and regioselective terminal functionalizations of acyclic monoterpenes 1 via benzenesulfenyl chloride addition followed by hydrolysis assisted by silica gel, dehydrochlorination under neutral or weakly basic condition, or dehydrochlorination by strongly basic treatment respectively providing β-hydroxy sulfides 3, terminal methallylic sulfides 4, or vinylsulfides 5 are developed.Conversion of 4 to terminal trans-allylic alcohols 10 via sulfoxides 9 by the Evans procedure is also described.
- Masaki, Yukio,Hashimoto, Kinji,Kaji, Kenji
-
p. 3481 - 3490
(2007/10/02)
-