The first enantiospecific synthesis of 2, a phosphonate isostere of phosphothreonine suitably protected for solid-phasepeptidesynthesis, has been achieved by coupling the highly face-selective conjugate addition of the lithium salt of Schöllkopf's bislactim ether to E-prop-2-enyl-phosphonates with a selective enzymatic carboxylic ester hydrolysis. The absolute configuration of the products has been
Conjugate Additions of 1-Propenylphosphonates to Metalated Schöllkopf's Bis-lactim Ether: Stereocontrolled Access to 2-Amino-3-methyl-4-phosphonobutanoic Acids
Diastereoselectivity in the conjugateaddition of metalated Schöllkopf's bis-lactim ethers 5a-e to (E)- and (Z)-1-propenylphosphonates 4a,b was studied experimentally and theoretically and utilized to achieve a direct and stereocontrolled synthesis of all four diastereoisomers of 2-amino-3-methyl-4-phosphonobutanoic acid, 6a,b and their enantiomers. The relative stereochemistry was assigned from an
In Situ Generation of Phosphoryl Alkylindiums and Their Synthetic Application to Arylalkyl Phosphonates via Palladium-Catalyzed Cross-Coupling Reactions
作者:Sanghyuck Kim、Cheol-Eui Kim、Boram Seo、Phil Ho Lee
DOI:10.1021/ol502540z
日期:2014.11.7
Phosphoryl alkylindium reagents are generated in situ from the direct insertion of indium with bromoalkyl phosphonates in the presence of CuCl, and their synthetic application to arylalkyl phosphonates is reported via a Pd-catalyzed cross-coupling reaction with tolerance of a diversity of functional groups including ester, ketone, aldehyde, nitrile, nitro, trifluoromethyl, chloride, methoxy, hydroxy, and amino.
Enantiospecific synthesis of 2-amino-3-methyl-4-phosphonobutanoic acids via 14-addition of lithiated Schöllkopf anion to prop-2-enylphosphonates
High diastereoselectivity in the conjugateaddition of lithiatedSchöllkopf'sbislactimethers to E- and Z- prop-2-enylphosphonates was utilized to achieve a direct asymmetric synthesis of all four diastereoisomers of 2-amino-3-methyl-4-phosphonobutanoic acid, i.e. (+)-(2S, 3R)-4a, (+)-(2S, 3S)-4b and their corresponding enantiomers. Their relative configuration was definitively assigned from an NMR