Mechanistic Studies on the O-Directed Free-Radical Hydrostannation of Disubstituted Acetylenes with Ph3SnH and Et3B and on the Iodination of Allylically Oxygenated α-Triphenylstannylalkenes
摘要:
The free-radical hydrostannation of 1 with Ph3SnH and catalytic Et3B in PhMe has been mechanistically probed. At high Ph3SnH concentrations, the O-directed hydrostannation pathway dominates, and 2 is formed with good selectivity (ca. 11.1:1). Substantially lower stannane/substrate concentrations increase the amount of tandem 5-exo-trig cyclization product 3 that is observed.
Provided are cyclic peptide analogs, conjugates comprising such compounds, and pharmaceutical compositions comprising such compounds and conjugates, and methods of treating cancer with such compounds and conjugates.
Kulokekahilide-2, a Cytotoxic Depsipeptide from a Cephalaspidean Mollusk <i>Philinopsis speciosa</i>
作者:Yoichi Nakao、Wesley Y. Yoshida、Yuuki Takada、Junji Kimura、Liu Yang、Susan L. Mooberry、Paul J. Scheuer
DOI:10.1021/np049949f
日期:2004.8.1
A cytotoxic depsipeptide, kulokekahilide-2 (1), was isolated from a cephalaspidean mollusk, Philinopsis speciosa. The structure elucidation of kulokekahilide-2 was carried out by spectroscopic analysis and chemical degradation. Kulokekahilide-2 showed potent cytotoxicity against several cell lines (P388, SKOV-3, MDA-MB-435, and A-10 with IC50 values ranging from 4.2 to 59.1 nM) indicating cancer cell selectivity.
Mechanistic Studies on the <i>O</i>-Directed Free-Radical Hydrostannation of Disubstituted Acetylenes with Ph<sub>3</sub>SnH and Et<sub>3</sub>B and on the Iodination of Allylically Oxygenated α-Triphenylstannylalkenes
作者:Paschalis Dimopoulos、Jonathan George、Derek A. Tocher、Soraya Manaviazar、Karl J. Hale
DOI:10.1021/ol051937d
日期:2005.11.1
The free-radical hydrostannation of 1 with Ph3SnH and catalytic Et3B in PhMe has been mechanistically probed. At high Ph3SnH concentrations, the O-directed hydrostannation pathway dominates, and 2 is formed with good selectivity (ca. 11.1:1). Substantially lower stannane/substrate concentrations increase the amount of tandem 5-exo-trig cyclization product 3 that is observed.