We have developed a mild and efficient catalyst-free [3 + 2] cyclization of isoquinoline imines and Morita–Baylis–Hillman carbonates. Various tetrahydropyrrolo[2,1-a]isoquinolines can be prepared in acceptable to excellent yields (up to 96%). The treatment of tetrahydropyrroloisoquinolines with DDQ afforded 5,6-dihydropyrrolo[2,1-a]isoquinolines in good yields (up to 90%). A one-pot synthesis of 5,6-dihydropyrrolo[2,1-a]isoquinolines has been achieved successfully (up to 86% yield). It should be noted that all the [3 + 2] cyclization, oxidation and one-pot reactions can be easily scaled up to the gram scale.

中文翻译：

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亚胺和Morita–Baylis–Hillman碳酸盐的无催化剂[3 + 2]环化：四氢吡咯并[2,1- a ]异喹啉和二氢吡咯并[2,1- a ]异喹啉的一般路线

我们已经开发出温和而有效的，无催化剂的异喹啉亚胺和Morita–Baylis–Hillman碳酸盐的[3 + 2]环化反应。可以以可接受的产率制备各种四氢吡咯并[2，1- a ]异喹啉（最高96％）。用DDQ处理四氢吡咯并异喹啉可以高产率（高达90％）得到5,6-二氢吡咯并[2,1- a ]异喹啉。一锅合成5,6-二氢吡咯并[2,1- a ]异喹啉已成功实现（最高收率86％）。应该注意的是，所有的[3 + 2]环化，氧化和一锅法反应都可以轻松放大至克级。