Abstract

Exploratory studies of the CpCo-mediated [2+2+2] cycloaddition of alkynes to the 2,3-double bond of benzo[b]furans (and some benzo[b]thiophenes) are presented, with the general aim to access morphinan substructures. The basic feasibility of constructing Co-complexed tetrahydrophenanthro[4,5-bcd]furans (and -thiophenes) in moderate to good yields is demonstrated, with complete to extensive diastereoselectivity. Limitations are the apparent necessity for bulky (silylated) monoalkynes, the lack of regioselectivity in the cocyclization with unsymmetrical alkynes, and the sensitivity of the ligands, both complexed and uncomplexed, with respect to ring opening and rearrangement.

Exploratory studies of the CpCo-mediated [2+2+2] cycloaddition of alkynes to the 2,3-double bond of benzo[b]furans (and some benzo[b]thiophenes) are presented, with the general aim to access morphinan substructures. The basic feasibility of constructing Co-complexed tetrahydrophenanthro[4,5-bcd]furans (and -thiophenes) in moderate to good yields is demonstrated, with complete to extensive diastereoselectivity. Limitations are the apparent necessity for bulky (silylated) monoalkynes, the lack of regioselectivity in the cocyclization with unsymmetrical alkynes, and the sensitivity of the ligands, both complexed and uncomplexed, with respect to ring opening and rearrangement.

中文翻译：

---

钴介导的炔烃与苯并[b]呋喃和苯并[b]噻吩的环[2 + 2 + 2]环加成反应：向吗啡酮的潜在途径

摘要

对CpCo介导的炔烃与苯并[ b ]呋喃（和一些苯并[ b ]噻吩的2,3-双键）的[2 + 2 + 2]环加成进行了探索性研究，其一般目的是获得吗啡喃子结构。证明了以中等至良好的产率构建共复合的四氢菲并[4,5- bcd ]呋喃（和-噻吩）的基本可行性，并具有完全至广泛的非对映选择性。局限性是明显的需要大体积的（甲硅烷基化的）单炔烃，在与不对称炔烃的共环化中缺乏区域选择性，以及配位体（无论是复杂的还是未复杂的）对开环和重排的敏感性。

对CpCo介导的炔烃与苯并[ b ]呋喃（和一些苯并[ b ]噻吩的2,3-双键）的[2 + 2 + 2]环加成进行了探索性研究，其一般目的是获得吗啡喃子结构。证明了以中等至良好的产率构建共复合的四氢菲并[4,5- bcd ]呋喃（和-噻吩）的基本可行性，并具有完全至广泛的非对映选择性。局限性是明显的需要大体积的（甲硅烷基化的）单炔烃，在与不对称炔烃的共环化中缺乏区域选择性，以及配位体（无论是复杂的还是未复杂的）对开环和重排的敏感性。