Seijiro Hosokawa

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The total synthesis of hibarimicinone, a potent v-Src tyrosine kinase inhibitor possessing thirteen stereogenic centers and an axial chirality, has been achieved. The key step to constructing the eight-ring skeleton was the double Michael–Dieckmann-type cyclization (Hauser annulation) using a thiolactone pseudo-dimer. These synthetic studies indicated the(More)
Recent progress of total syntheses in our laboratory has been described along with our background and methodologies. The target bioactive polyketides are classified into three categories according to their structures: (i) lactone-fused polycyclic compounds [(+)-cochleamycin A, (+)-tubelactomicin A, and (-)-tetrodecamycin], (ii) aromatic compounds(More)
[reaction: see text] The first enantioselective total synthesis of convolutamydines B and E has been achieved using our vinylogous Mukaiyama aldol reaction. The synthesis features highly diastereoselective vinylogous Mukaiyama aldol reaction with isatin instead of aldehydes to construct a chiral center of convolutamydines. Additionally, the absolute(More)
Chemokine (C-C motif) receptor 8 (CCR8), the chemokine receptor for chemokine (C-C motif) ligand 1 (CCL1), is expressed in T-helper type-2 lymphocytes and peritoneal macrophages (PMφ) and is involved in various pathological conditions, including peritoneal adhesions. However, the role of CCR8 in inflammatory responses is not fully elucidated. To investigate(More)
The sarcodictyins A-F and eleutherobin comprise a family of marine-derived diterpenoids with potent cytotoxicities against various tumor cell lines. Investigations have revealed that several of these compounds exert their cytotoxic effects through tubulin binding in a mechanism analogous to that of the clinical anticancer drug Taxol. The biological(More)
Remote asymmetric induction by the vinylogous Mukaiyama aldol reaction using the acetate-type vinylketene silyl N,O-acetal possessing a chiral auxiliary has been achieved. The silyl N,O-acetal derived from crotonate and l-valine afforded the O-silylated 5R- and 5S-adducts selectively by treatment with SnCl4 and BF3·OEt2, respectively. The SnCl4-mediated(More)
Stereoselective vinylogous Mukaiyama aldol reactions using the Z,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary, derived from (E)-3-pentenoic acid and l-valine, have been achieved. The reaction proceeded smoothly to give a syn adduct in high stereoselectivity. Since the products possess structures including δ-alkoxy-γ-methyl-α,β-unsaturated(More)
A concise and straightforward synthesis of 2,4,6-trimethyloctanoates was established by using the sequence of the vinylogous Mukaiyama aldol reaction and regio- and stereoselective reduction reactions. All isomers were obtained selectively in a few steps. The short step synthesis of septoriamycin A, an antimalarial and antileishmanial agent, has been(More)
Stereoselective bromination of the E,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary has been achieved and applied to introduction of heteroatom at γ-position of α,β-unsaturated imide. The reactions proceeded in high stereoselectivity. Total synthesis of pellasoren A, an antitumor propionate from the myxobacteriun Sorangium cellulosum, has been(More)
[structure: see text] A convergent total synthesis of khafrefungin was accomplished on the basis of (1) the highly stereoselective TiCl4-mediated vinylogous Mukaiyama aldol reaction using vinylketene silyl N,O-acetal and (2) syn-selective aldol reaction of enal 5a and ethyl ketone 6 followed by anti-dehydration under Mitsunobu conditions.