Diastereodivergent Hydroxyfluorination of Cyclic and Acyclic Allylic Amines: Synthesis of 4-Deoxy-4-fluorophytosphingosines
作者:Alexander J. Cresswell、Stephen G. Davies、James A. Lee、Melloney J. Morris、Paul M. Roberts、James E. Thomson
DOI:10.1021/jo301056r
日期:2012.9.7
ammonium ion. Regioselective and stereospecificepoxide ring-opening by transfer of fluoride from a BF4– ion (an SN2-type process at the carbon atom distal to the ammonium moiety) then occurs in situ to give the corresponding amino fluorohydrin. Alternatively, an analogous reaction using 20 equiv of HBF4·OEt2 results in preferential epoxidation of the opposite face of the olefin, which is followed by regioselective
Substrate-Regiocontrolled Synthesis of Enantioenriched Allylic Amines by Palladium-Catalysed Asymmetric Allylic Amination: Formal Synthesis of Fagomine
or the protected derivative, respectively. Unhindered primary amines can be used as nucleophiles, thus enlarging the scope of the Pd/DACH catalytic system. Hydrogen bonding involving the free hydroxy group in the unprotected allylic carbonate is proposed to be responsible for the control of the regioselectivity to afford branched isomers, obtained in high ee. A short and enantioselective formal synthesis
direct oxidation of unprotected amino alcohols to their corresponding amino carbonylcompounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds
Development of the Ireland-Claisen Rearrangement of Allyl-2-alkoxyacetate Bearing an Allylic Amine and the Transformation to 3-Hydroxy-4-hydroxymethylpyrrolidine
An unprecedented Ireland–Claisen rearrangement of allylglycolate bearing an allylic amine was realized, affording the corresponding product with excellent diastereoselectivity and in high yield. The product was analyzed by X‐ray crystallography, and demonstrated the transformation to the 4‐hydroxymethylpyrrolidin‐3‐ol.