Samarium(II)-promoted radical spirocyclization onto an aromatic ring

被引:59
作者
Ohno, H [1 ]
Okumura, M [1 ]
Maeda, S [1 ]
Iwasaki, H [1 ]
Wakayama, R [1 ]
Tanaka, T [1 ]
机构
[1] Osaka Univ, Grad Sch Pharmaceut Sci, Suita, Osaka 5650871, Japan
关键词
D O I
10.1021/jo034767w
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Samarium(II)-mediated spirocyclization onto an aromatic ring was achieved by the reaction of methyl 4-(4-oxoalkyl)benzoates with SmI2 in the presence of i-PrOH and HMPA, yielding methyl 1-alkyl-1-hydroxyspiro[4.5]dec-6-ene-8-carboxylates in moderate to high yields. Utilizing this chemistry, spiro[3.5] and -[5.5] systems, and sterically congested spiro[4.5] systems, were easily synthesized. For the successful conversion, appropriate activation of the aromatic ring has proven to be extremely important: while an ester or amide functionality on the aromatic ring can promote the spirocyclization, a sulfonamide substituent causes ortho cyclization.
引用
收藏
页码:7722 / 7732
页数:11
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