Facile synthesis of 2,4-dienals via an arsonium salt and its application to some natural products

✍ Scribed by Jian-Hua Yang; Li-Lan Shi; Wen-Juan Xiao; Xue-Qing Wen; Yao-Zeng Huang

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 576 KB
• Volume: 1
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.520010111

✦ Synopsis

2,4-Dienals were synthesized conveniently by using a new for~?ivlri?ylolefination method. The aldehydes were reacted with formylallyltriphenylarsonium bromide (2) in Et20-THF-H20 (9 : 1 : 0.05) in the presence of K2C03 at room temperature to give (2E,4E)and (2E,4Z)-dienals, in favor of the former. They could be easily separated by chromatography, and the latter, in CH2C12, could be converted to the former on treatment with a catalytic amount o f iodine in daylight. The configurations of the (E,E) products have been conveniently identified by ' H NMR determined in C6D6. The syntheses of two natural products, navenone A und Otanthus maritima amide, by this method are also reported in detail.

A 2,4-Dienal is an important intermediate from which a variety of biologically active natural products can be synthesized. Moreover, some 2,4dienals themselves are biologically active; for example, a metabolite (l), isolated from the red algae Laurencia hybrida, possesses antimicrobial activity r11.