Regiospecific Bromination of 3-Methylindoles with NBS and Its Application to the Concise Synthesis of Optically Active Unusual Tryptophans Present in Marine Cyclic Peptides<sup>1</sup>
作者:Ruiyan Liu、Puwen Zhang、Tong Gan、James M. Cook
DOI:10.1021/jo971067g
日期:1997.10.1
A regiospecific bromination of substituted 3-methylindoles at either the C(3) alkyl moiety or the C(2) position was achieved via a free radical bromination or electrophilic process, respectively. The regiospecificity of the bromination could be controlled by variation of both the substituent and the N(1) protecting group on the indole ring. In addition, enantiospecific syntheses of 5-methoxytryptophan
在C(3)烷基部分或C(2)位置取代的3-甲基吲哚的区域特异性溴化分别通过自由基溴化或亲电过程实现。溴化反应的区域特异性可以通过取代基和吲哚环上的N(1)保护基的变化来控制。另外,由双官能二溴吲哚分三步合成了5-甲氧基色氨酸(20)和5-羟基-6-氯色氨酸(21c)的对映体专一性,以及光学活性的2-溴色氨酸乙酯26a,b或它们的取代衍生物的简明合成。通过上述区域特异性过程实现。