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Showing papers by "Kazuo Nagasawa published in 1994"

Journal Article•DOI•
Synthetic study of marine macrolide swinholide A: stereocontrolled synthesis of the C11-C32 segment

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Tadashi Nakata, Toshiya Komatsu, Kazuo Nagasawa
15 Nov 1994-Chemical & Pharmaceutical Bulletin
TL;DR: The C24-C32 segment 4 of swinholide A (1) was stereoselectively synthesized starting from (S)-methyl 3-hydroxybutyrate as mentioned in this paper.
Abstract: The C24-C32 segment 4 of swinholide A (1) was stereoselectively synthesized starting from (S)-methyl 3-hydroxybutyrate, and the convergent synthesis of the C11-C32 segment 5 was accomplished via stereoselective aldol condensation of 3 and 4

26 citations

Journal Article•DOI•
Synthetic study of marine macrolide swinholide A. stereocontrolled synthesis of the C11 - C23 segment

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Tadashi Nakata, Toshiya Komatsu, Kazuo Nagasawa, Haruo Yamada1, Takashi Takahashi1 •
Tokyo Institute of Technology1
31 Oct 1994-Tetrahedron Letters
TL;DR: In this paper, the C11-C23 segment of swinholide A was synthesized stereoselectively starting from (S)-malic acid via double nitroaldol reaction under high pressure and differentiation of the left and right parts of the symmetric compound 10 as the key steps.

22 citations

Journal Article•DOI•
Activated basic alumina promotes a mild, clean and high-yield racemization-free synthesis of t-butyl esters from chiral acid bromides and t-butyl alcohol

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Kazuo Nagasawa, Keiko Ohhashi, Asami Yamashita, Keiichi Ito
01 Feb 1994-Chemistry Letters
TL;DR: Esterification of a variety of acid bromides having even steric bulkiness with t-BuOH/activated basic alumina gave the corresponding t-butyl esters in good to excellent yields.
Abstract: Esterification of a variety of acid bromides having even steric bulkiness with t-BuOH/activated basic alumina gave the corresponding t-butyl esters in good to excellent yields. In the case of chiral acid bromides, no racemization has been ascertained for the first time.

18 citations