Cyclopropyl Grignard reagents react with carbonyl compounds in the presence of diethyl phosphite to give homoallylicbromides. The reaction is effectively carried out under mild conditions in a one-pot fashion with moderate to good yields.
Iridium-Catalyzed Dynamic Kinetic Isomerization: Expedient Synthesis of Carbohydrates from Achmatowicz Rearrangement Products
作者:Hao-Yuan Wang、Ka Yang、Scott R. Bennett、Sheng-rong Guo、Weiping Tang
DOI:10.1002/anie.201503151
日期:2015.7.20
A highly stereoselective dynamickineticisomerization of Achmatowiczrearrangementproducts was discovered. This new internal redox isomerization provided ready access to key intermediates for the enantio‐ and diastereoselective synthesis of a series of naturally occurring sugars. The nature of the de novo synthesis also enables the preparation of both enantiomers.
Palladium‐Catalyzed Regioselective and Diastereoselective
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‐Glycosylation by Allyl‐Allyl Coupling
作者:Junhao Li、Nan Zheng、Xuelun Duan、Rui Li、Wangze Song
DOI:10.1002/adsc.202001136
日期:2021.2.2
A Pd‐catalyzed C‐glycosylation reaction was developed by allyl‐allyl coupling process using Achmatowicz rearrangement products as donors and methylcoumarins as acceptors under mild conditions. This method featured regio‐ and diastereoselectivities, stereodivergent synthesis of C‐glycosides. The glycosyl donors with controlled stereodiversity and glycosyl acceptors with fluorescent performace further
A method to extend the scope of the aza‐Piancatelli reaction between 2‐furylcarbinols and anilines is depicted. We found that 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) is the solvent of choice for this transformation, as it outcompetes the usual solvents in terms of rate and yield. Side reactions and other issues raised by the title reaction are prevented, thereby providing an avenue to complex molecules
Divergent Synthesis of Dihydropyranone Stereoisomers via N‐Heterocyclic Carbene Catalysis
作者:Changgui Zhao、Jian Wang
DOI:10.1002/adsc.201801639
日期:2019.4
We recently developed a novel chiral N‐heterocyclic carbene (NHC) catalyzed dynamic kinetic enantioselective acylation (DKEA) and dynamic kinetic diastereoselective acylation (DKDA) of Achmatowicz rearrangement products to generate useful intermediates for the further synthesis of carbohydrates. In this update, we describe a divergent NHC catalytic strategy for the stereoselective preparation of all