Synthetic studies on Lythraceae alkaloids via (3+2)cycloaddition. II. Total synthesis of (.+-.)-decaline and (.+-.)-vertaline.
作者:KOZO SHISHIDO、KATSURA TANAKA、KEIICHIRO FUKUMOTO、TETSUJI KAMETANI
DOI:10.1248/cpb.33.532
日期:——
An efficient total synthesis of (±)-decaline and (±)-vertaline, lactonic biphenyl ether Lythraceae alkaloids, was achieved. The [3+2] cycloaddition of the nitrone (24) with the olefin (10), prepared via the Ullmann reaction catalyzed by a phase-transfer reagent, produced the adduct (11) which, upon treatment with methanesulfonyl chloride followed by reductive cleavage of the N-O bond, gave the isomeric quinolizidinols (13 and 14) in a one-pot operation. Through the use of inter-and intramolecular Mitsunobu reaction as an inversion procedure at C-2, 13 was converted into (±)-decaline (1). On the other hand, the cis-quinolizidinol (14) was transformed in two steps to (±)-vertaline (2).
我们实现了(±)-癸氨喹和(±)-缬氨喹内酯联苯醚枸杞生物碱的高效全合成。通过相转移试剂催化的乌尔曼反应制备的腈酮(24)与烯烃(10)的[3+2]环加成反应生成了加合物(11),该加合物经甲磺酰氯处理后,N-O 键被还原裂解,从而在一锅操作中生成了异构的喹嗪二醇(13 和 14)。通过分子间和分子内的 Mitsunobu 反应作为 C-2 的反转过程,13 被转化为 (±)-decaline (1)。另一方面,顺式喹唑烷醇 (14) 分两步转化为(±)-缬氨酸 (2)。