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pro vyhledávání: '"Ken S. Feldman"'
Autor:
Ken S. Feldman
Publikováno v:
ARKIVOC, Vol 2003, Iss 6, Pp 179-190 (2003)
Externí odkaz:
https://doaj.org/article/004e29cfed0d46879aae2181deadca0b
Publikováno v:
Tetrahedron Letters. 56:3564-3566
The carbofunctionalization of 2-bromo-N-benzyl indole via lithium–bromide exchange is presented. The reaction scope is demonstrated by providing a variety of substrate examples that deliver carbofunctionalized products in good-to-excellent yields.
Autor:
Brandon R. Selfridge, Ken S. Feldman
Publikováno v:
The Journal of Organic Chemistry. 78:4499-4511
The enantiomer of the bicyclic lomaiviticin aglycone A core was prepared via a two-directional, divergent approach featuring (1) a double Ireland Claisen rearrangement to establish key core bonds with correct relative stereochemistry and (2) a double
Autor:
Ken S. Feldman, Joshua F. Antoline
Publikováno v:
Tetrahedron. 69:1434-1445
The pentacyclic Melodinus alkaloid (±)-meloscine was synthesized in 19 chemical steps from 2-bromobenzaldehyde through a route featuring an allenyl azide cyclization cascade to deliver the core azabicyclo[3.3.0]octane substructure. Peripheral functi
Autor:
Tamara S. Folda, Ken S. Feldman
Publikováno v:
The Journal of organic chemistry. 81(11)
A synthesis route to the pentacyclic alkaloid (−)-gilbertine, which features a cyclization cascade passing through a transient indolidene intermediate, was pursued. A key stereochemical relationship was set via a Nicholas-type enolate alkylation. U
Autor:
Jetze J. Tepe, Shun Su, Ken S. Feldman, Amanda P. Skoumbourdis, Matthew D. Fodor, Ian B. Seiple, Theresa A. Lansdell, Nicole M. Hewlett, Phil S. Baran
Publikováno v:
Journal of Natural Products. 75:980-985
We report herein that the oroidin-derived alkaloids palau'amine (1), dibromophakellin (2), and dibromophakellstatin (3) inhibit the proteolytic activity of the human 20S proteasome as well as the (i)20S immunoproteasome catalytic core. Palau'amine is
Autor:
Ken S. Feldman, Brandon R. Selfridge
Publikováno v:
Tetrahedron Letters. 53:825-828
The diastereoselectivity of Ireland–Claisen rearrangements of allylic glycolates is dependent on the E:Z ratio of the silyl ketene acetals, the alkene geometry in the allyl unit, and the transition state topography. High yields and excellent diaste
Publikováno v:
The Journal of Organic Chemistry. 76:5042-5060
Exploratory oxidative cyclization studies on cyclopentanelated and cyclohexenelated oroidin derivatives utilized Pummerer chemistry to generate pentacyclic structures related to the palau'amine family of sponge metabolites. Stereochemical issues were
Autor:
Ken S. Feldman, Ahmed Yimam Nuriye
Publikováno v:
Organic Letters. 12:4532-4535
A pentacyclic model system featuring the trans azabicyclo[3.3.0]octane unit of dibromopalau'amine was prepared with complete diastereoselectivity in the polycyclic core from a tricyclic precursor. The key transformations of this sequence include (a)
Autor:
Ken S. Feldman, Paiboon Ngernmeesri
Publikováno v:
Organic Letters. 12:4502-4505
The conversion of a cycloheptannelated indole platform into the heptacyclic core structure of dragmacidin E proceeded over nine steps. Key sequences include a cyclocondensation to form an intermediate dihydropyrazinone ring and the conversion of a cy