Transformation of carbonyl to vinylidene groups in the π-conjugated peripheral substituent of chlorophyll derivatives by Tebbe reagent
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- 作者：Hitoshi Tamiakia ; tamiaki@fc.ritsumei.ac.jp" class="auth_mail" title="E-mail the corresponding author ; Kazuki Tsujia ; b ; Shinnosuke Machidaa ; Misato Teramuraa ; Tomohiro Miyatakeb
- 关键词：Carbonyl methylenation ; Methylene titanium ; Pheophorbide ; Semi-synthetic modification
- 刊名：Tetrahedron Letters
- 出版年：2016
- 出版时间：17 February 2016
- 年：2016
- 卷：57
- 期：7
- 页码：788-790
- 全文大小：257 K
文摘
The 131-oxo-moiety of chlorophyll-a derivatives including methyl (pyro)pheophorbides-a, mesopyropheophorbide-a, and bacteriopheophorbide-d possessing vinyl, ethyl, and 1-hydroxyethyl groups, respectively, at the 3-position was transformed into the corresponding exo-methylene group by treatment of Tebbe reagent. The synthetic procedures were useful for the regioselective conversion of the carbonyl to vinylidene group at the 3-position and naturally occurring chlorophyll-d (3-CHO) was successfully modified to chlorophyll-a (3-CH
CH2). Under the methylenation conditions, ester–carbonyl, hydroxy, and allyl groups in the peripheral substituents were tolerant as well as an acid-labile magnesium at the central position of chlorophylls.
CH2). Under the methylenation conditions, ester–carbonyl, hydroxy, and allyl groups in the peripheral substituents were tolerant as well as an acid-labile magnesium at the central position of chlorophylls.