Palladium-catalyzed silylene-1,3-diene [4 + 1] cycloaddition with use of (aminosilyl)boronic esters as synthetic equivalents of silylene.
Palladium-catalyzed silylene-1,3-diene [4 + 1] cycloaddition with use of (aminosilyl)boronic esters as synthetic equivalents of silylene.
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DOI：
10.1021/ja907170p
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发表时间：
2009-11
影响因子：
15
通讯作者：
Toshimichi Ohmura;K. Masuda;I. Takase;M. Suginome
中科院分区：
文献类型：
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作者：
Toshimichi Ohmura;K. Masuda;I. Takase;M. Suginome
硅原子上带有二烷基氨基的甲硅烷基硼酯在钯催化剂存在下与 1,3-二烯反应，通过有效的甲硅烷基从甲硅烷基硼酯到 1,3-二烯的转移，以高产率得到硅杂环戊-3-烯（即 2,5-二氢硅杂环）。 [4+1]环加成适用于母体1,3-丁二烯和具有甲硅烷氧基、氰基和酯基的各种单、二和三取代的1,3-二烯。在与 5,7-十二碳二烯的任一立体异构体的反应中发生立体特异性环形成：(E,E)-二烯产生顺式产物，而在异构体(E,Z)-二烯的反应中观察到反式产物的选择性形成。 [4+1]环加成，然后用DDQ或四氯苯醌脱氢，得到2,4-和2,5-二芳基硅杂环戊二烯。
Silylboronic esters bearing a dialkylamino group on the silicon atoms reacted with 1,3-dienes in the presence of a palladium catalyst to give silacyclopent-3-enes (i.e., 2,5-dihydrosiloles) in high yields via efficient silylene transfer from the silylboronic ester to the 1,3-dienes. The [4 + 1] cycloaddition was applicable to the parent 1,3-butadiene and various mono-, di-, and trisubstituted 1,3-dienes having silyloxy, cyano, and ester groups. Stereospecific ring formation took place in the reaction with either stereoisomer of 5,7-dodecadiene: the (E,E)-diene gave the cis product, whereas selective formation of the trans product was observed in the reaction of the isomeric (E,Z)-diene. The [4 + 1] cycloaddition followed by dehydrogenation with DDQ or chloranil afforded 2,4- and 2,5-diarylsiloles.