Thionoesters as 1,2-Dipolarophiles for [4+2] Cycloaddition with Cyclobutanones
Thionoesters as 1,2-Dipolarophiles for [4+2] Cycloaddition with Cyclobutanones
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硫代酯作为 1,2-亲偶极试剂，用于与环丁酮的 [4 2] 环加成反应
DOI：
10.1002/ajoc.201900156
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Matsumoto;Y.; Tsuji;T.; Nakatake;D.; Yazaki;R.; Ohshima;T.
描述了硫代酸酯作为1，2-偶极亲电体用于与环丁酮的[4+2]环加成的效用。[4+2]环加成反应通过使用容易获得的TiCl 4以高产率和高非对映选择性提供了在生物活性天然产物中发现的四氢噻喃。该合成方法适用于广泛的硫代酸酯和环丁酮。产物的酮和S，O-缩酮官能团可以以优异的非对映选择性被还原。此外，C−O键转化为C−C键，提供连续的四取代碳中心。
The utility of thionoester as a 1,2‐dipolarophile for [4+2] cycloaddition with cyclobutanones is described. The [4+2] cycloaddition reaction provided tetrahydrothiopyran, which is found in biologically active natural products, in high yield with high diastereoselectivity by using readily available TiCl4. This synthetic method was applicable to a wide range of thionoesters and cyclobutanones. The ketone andS,O‐ketal functionalities of the product could be reduced with excellent diastereoselectivity. Furthermore, the C−O bond was transformed into a C−C bond, affording contiguous tetrasubstituted carbon centers.