An enantioselective synthesis of iso-, isothio-, and isoselenohydantoin and diketopiperazine-fused tetrahydroisoquinolines from l-Dopa was reported. The route consists of an Pictet-Spengler reaction of ( S)-2-amino-3-(3,4-dimethoxyphenyl)propanoates with various aldehydes to afford diastereomeric tetrahydroisoquinolines. Next step, the tetrahydroisoquinolines were further reacted with iso-, isothio-, or isoselenocyanates to construct hydantoin. Similarly, the diketopiperazine moiety was constructed by subjecting tetrahydroisoquinolines to a condensation reaction with chloroacetyl chloride followed by nucleophilic addition with various primary amines.

中文翻译：

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通过Pictet-Spengler反应对乙内酰脲和二酮哌嗪融合的四氢异喹啉进行对映选择性合成。

据报道，从I-Dopa对映异构合成异-，异硫-和异亚硒基乙内酰脲和二酮哌嗪融合的四氢异喹啉。该路线由（S）-2-氨基-3-（3,4-二甲氧基苯基）丙酸酯与各种醛的Pictet-Spengler反应组成，以提供非对映体四氢异喹啉。下一步，使四氢异喹啉与异氰酸酯，异硫氰酸酯或异鲸蜡氰酸酯进一步反应以构建乙内酰脲。类似地，通过使四氢异喹啉与氯乙酰氯进行缩合反应，然后与各种伯胺进行亲核加成，来构建二酮哌嗪部分。