Synthetic Studies of Antitumor Macrolide Rhizoxin: Stereoselective Syntheses of the C(1)−C(9) and C(12)−C(26) Subunits
作者:Steven D. Burke、Jian Hong、Joseph R. Lennox、Andrew P. Mongin
DOI:10.1021/jo980754k
日期:1998.10.1
Horner-Wadsworth-Emmons reaction. The central segment 4 and the oxazole chromophore side chain 3 were coupled using another highlystereoselectiveHorner-Wadsworth-Emmonsreaction. Two different lactone subunits [C(1)-C(9) segment 5 and C(3)-C(10) segment 47] were also prepared, employing a thermodynamically controlled diastereotopic group differentiation tactic for establishing the C(5) stereochemistry
2,3-<i>O</i>-(3-Pentylidene)-D-glyceraldehyde and 2,3-<i>O</i>-(3-Pentylidene)-L-glyceraldehyde: Convenient Glyceraldehyde Surrogates Obtained via a Novel Periodate-Based Oxdation System
作者:Christopher R. Schmid、David A. Bradley
DOI:10.1055/s-1992-26170
日期:——
The synthesis of two novel glyceraldehyde surrogates, 2,3-O-(3-pentylidene)-D-glyceraldehyde (2) and 2,3-O-(3-pentylidene)-L.-glyceraldehyde (3) is presented. Synthesis, handling and storage advantages of 2 and 3 over the conventionally employed 2,3-O-isopropylidene-D-glyceraldehyde (1) are discussed. The 3-pentanone-derived protecting group facilitates the extraction of product from aqueous oxidation solutions, while the 3-pentanone liberated on ketal deprotection can be efficiently removed at reduced pressures. The synthesis employs a buffered potassium periodate oxidation which offers significant advantages over sodium periodate in glycol cleavage reactions.
Synthetic studies toward amphidinolide A: Synthesis of fully functionalized subunits
作者:Lamont R. Terrell、Joseph S. Ward、Robert E. Maleczka
DOI:10.1016/s0040-4039(99)00438-4
日期:1999.4
A retrosynthetic breakdown of amphidinolide A affords four fragments A-D and illustrates the main synthetic challenges of this molecule. A concise stereoselective synthesis of the four appropriately functionalized subtargets is described.
Asymmetric Induction in Intramolecular [2 + 2]-Photocycloadditions of 1,3-Disubstituted Allenes with Enones and Enoates
作者:Erick M. Carreira、Curtis A. Hastings、Mary S. Shepard、Lori A. Yerkey、Dan B. Millward
DOI:10.1021/ja00094a017
日期:1994.7
Irradiation of optically active allenes (89-92% ee) appended to enones and enoates affords alkylidenecyclobutane photoadducts with high levels of asymmetricinduction (83-100%) derived exclusively from the allene fragment. The substrates studied include allenes tethered to enones such as 1,3-cyclohexanedionea nd 1,3-cyclopentanedione, as well as allenes tethered to functionalized coumarins. The enantiomer
Highly Diastereoselective Synthesis of a HCV NS5B Nucleoside Polymerase Inhibitor
作者:Yong-Li Zhong、Ed Cleator、Zhijian Liu、Jianguo Yin、William J. Morris、Mahbub Alam、Brian Bishop、Aaron M. Dumas、John Edwards、Adrian Goodyear、Peter Mullens、Zhiguo Jake Song、Michael Shevlin、David A. Thaisrivongs、Hongming Li、Edward C. Sherer、Ryan D. Cohen、Jingjun Yin、Lushi Tan、Nobuyoshi Yasuda、John Limanto、Antony Davies、Kevin R. Campos
DOI:10.1021/acs.joc.8b02500
日期:2019.4.19
An asymmetric synthesis of HCV NS5B nucleoside polymerase inhibitor (1) is described. This novel route features several remarkably diastereoselective and high-yielding transformations, including construction of the all-carbon quaternary stereogenic center at C-2 via a thermodynamic aldol reaction. A subsequent glycosylation reaction with activated uracil via C-1 phosphate and installation of the cyclic