Published as part of the Special Topic Modern Radical Methods and their Strategic Applications in Synthesis

Dedicated to Professor Sambasivarao Kotha, IIT Bombay, on the occasion of his 60^th birthday.

Abstract

An efficient strategy was developed for the stereoselective construction of oxa- and aza-angular triquinanes employing a cascade 5-exo-trig radical cyclization to vinylogous carbonates and carbamates. The radical precursors are readily prepared from 2-(hydroxymethyl)cyclopentenone/cyclohexenones. High diastereoselectivity is observed for the formation of angular oxa- and azatriquinanes. Diastereoselectivity drops when six-membered radical precursors are used. The strategy is found to be useful to incorporate synthetically challenging moieties such as spiroindoline, lactone-bearing, and uracil-fused angular triquinanes in a concise manner.

An efficient strategy was developed for the stereoselective construction of oxa- and aza-angular triquinanes employing a cascade 5-exo-trig radical cyclization to vinylogous carbonates and carbamates. The radical precursors are readily prepared from 2-(hydroxymethyl)cyclopentenone/cyclohexenones. High diastereoselectivity is observed for the formation of angular oxa- and azatriquinanes. Diastereoselectivity drops when six-membered radical precursors are used. The strategy is found to be useful to incorporate synthetically challenging moieties such as spiroindoline, lactone-bearing, and uracil-fused angular triquinanes in a concise manner.

中文翻译：

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级联自由基环化成乙烯基碳酸盐/氨基甲酸酯，用于合成氧杂和氮杂角三喹烷：非对映选择性取决于自由基前体的环大小

作为特别主题“现代自由基方法及其在合成中的战略应用”的一部分发布

专用于Sambasivarao Kotha教授，IIT孟买，他的60之际^个生日。

抽象的

开发了一种有效的策略，用于立体选择性地构建氧杂和氮杂角的三喹烷，采用级联的5 - exo - trig自由基环化成乙烯基碳酸酯和氨基甲酸酯。自由基前体易于由2-（羟甲基）环戊烯酮/环己烯酮制备。观察到高的非对映选择性，形成有角的氧杂和氮杂三喹烷。当使用六元自由基前体时，非对映选择性下降。发现该策略对于以简洁的方式并入具有合成挑战性的部分例如螺二氢吲哚，带有内酯和尿嘧啶融合的角三喹烷是有用的。

开发了一种有效的策略，用于立体选择性地构建氧杂和氮杂角的三喹烷，采用级联的5 - exo - trig自由基环化成乙烯基碳酸酯和氨基甲酸酯。自由基前体易于由2-（羟甲基）环戊烯酮/环己烯酮制备。观察到高的非对映选择性，形成有角的氧杂和氮杂三喹烷。当使用六元自由基前体时，非对映选择性下降。发现该策略对于以简洁的方式并入具有合成挑战性的部分例如螺二氢吲哚，带有内酯和尿嘧啶融合的角三喹烷是有用的。