論文 - ウヤヌク　ムハメット

Catalytic Diastereoselective Polycyclization of Homo(polyprenyl)arene Analogues Bearing Terminal Siloxyvinyl Groups 査読有り

Muhammet Uyanik, Kazuaki Ishihara, Hisashi Yamamoto

Organic Letters   8 巻 ( 24 ) 頁： 5649 - 5652   2006年11月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Highly diastereoselective polycyclization of homo(polyprenyl)arene analogues bearing terminal siloxyvinyl groups was catalyzed by tin(IV) chloride (10 mol %). The cyclizations of tert-butyldiphenylsilyl and triisopropylsilyl polyenol ethers gave 4(equatorial)- and 4(axial)-siloxypolycycles as major isomers, respectively. The strong nucleophilicity of pro-C(9), a (6E) geometry, and a bulky silyl group effectively favored the 4-preference, whereas the weak nucleophilicity of pro-C(9), a (6Z)-geometry, and less steric hindrance of a silyl group favored the 4-preference.

DOI： 10.1021/ol062378t

Biomimetic Synthesis of Acid-Sensitive (-)- and (+)-Caparrapi Oxides, (-)- and (+)-8-Epicaparrapi Oxides, and (+)-Dysifragin Induced by Artificial Cyclases 招待有り 査読有り

Muhammet Uyanik, Kazuaki Ishihara, Hisashi Yamamoto

Bioorg. Med. Chem.   13 巻 ( 17 ) 頁： 5055 - 5065   2005年5月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Asymmetric total syntheses of acid-sensitive (-)- and (+)-caparrapi oxides (1) and (+)-8-epicaparrapi oxide (2) from farnesol (10) are achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Br?nsted acid (chiral LBA)-induced polyene cyclization as key steps. The relative configuration of (+)-dysifragin (4) is determined by a single-crystal X-ray diffraction and its total synthesis is accomplished by the diastereoselective epoxidation of (+)-1. Furthermore, (-)-1 can be directly synthesized from (S)-nerolidol (3) and (R)-LBA with 88% ds by reagent control, which overcame substrate control, while (-)-2 is obtained from (R)-3 and (R)-LBA with >99% ds by the double asymmetric induction.

DOI： 10.1016/j.bmc.2005.04.029

Biomimetic Synthesis of Acid-Sensitive (-)-Caparrapi Oxide and (+)-8-Epicaparrapi Oxide Induced by Artificial Cyclases 査読有り

Muhammet Uyanik, Hideaki Ishibashi, Kazuaki Ishihara, Hisashi Yamamoto

Organic Letters   7 巻 ( 8 ) 頁： 1601 - 1604   2005年3月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Asymmetric total syntheses of acid-sensitive (-)-caparrapi oxide (1) and (+)-8-epicaparrapi oxide (2) from farnesol (9) were achieved using Sharpless-Katsuki epoxidation and Lewis acid-assisted chiral Brnsted acid (chiral LBA)-induced polyene cyclization as key steps. Furthermore, (-)-1 could be directly synthesized from (S)-nerolidol (3) and (R)-LBA with 88% ds by reagent control which overcame substrate control, while (-)-2 was obtained from (R)-3 and (R)-LBA with >99% ds by the double-asymmetric induction.

DOI： 10.1021/o1050295r