1997 年 117 巻 8 号 p. 468-485
The synthesis of natural products involves the following two fundamental procedures : the synthesis of a key intermediate (which will be synthesized in a convergent way) and transformation of the key intermediate to various natural products (which should be synthesized in a divergent process). Either of these procedures requires new generally applicable synthetic ideas or methods for the efficient synthesis of the natural products. On the basis of this concept, the total syntheses of spiro-type alkaloids in Amaryllidaceae, erythrinan, and homoerythrinan group are described, and the application of several new synthetic methods which were developed during the syntheses is abso discussed.