Synthesis of Biologically Active Compounds Using Potential Utility of Transition Metals

(1)碘化钐介导的芳香环螺旋环化。钐（II）试剂的还原和碳-碳键形成在有机合成中引起了广泛的兴趣。相比之下，钐（II）介导的自由基环化到芳烃环上直到最近才出现。2000年，我们发现钐（II）可以有效地促进芳香甲氧基的自由基取代，从而得到环化产物。基于这些结果，从在酯基对位上具有氧烷基的苯甲酸酯开始，实现了在芳香环上的自由基螺旋环化。(2)钯催化亚砜基锌化的研究进展。亚砜基阴离子是合成各种亚砜基化合物的重要反应中间体。我们首次发现，在Pd(0)催化剂（Org）存在下，用Et_2Zn处理1炔基亚氧化物可以生成亚亚基锌。列托人。， 2001, 3, 3627)。由于该方法易于在非常温和的反应条件下生成，因此可以立体选择性地合成各种功能化乙烯基亚氧化物。近年来，氨基烯类化合物由于是构建各种氮杂环的多用途底物而引起了人们的广泛关注。我们发现了一种使用钯(0)/二乙基锌体系合成烯烃（包括氨基烯烃）的通用且高效的方法：用二乙基锌和钯(0)催化剂处理2溴链2烯1醇的甲磺酸盐或三氯乙酸盐，可以得到各种具有氨基烷基、烷基或芳基取代基的烯烃，收率很高（J. Org, Chem. 2002, 67, 1359）。

(1) Samarium(II) IodideMediated Spirocyclization onto an Aromatic Ring. Both the reduction and carboncarbon bond formation with samarium(II) reagents have attracted much interest in organic synthesis. In contrast, samarium(II) mediated radical cyclization onto an arene ring had been unprecedented until recently. In 2000, we found that a radical ipso substitution of the aromatic methoxy group is effectively promoted by samarium(II) to afford the cyclized products. Based on these results, the radical spirocyclization onto an aromatic ring have been realized starting from benzoate possessing an oxoalkyl group at the para position to the ester group (Chem. Commun. 2002, 316)(2) Development of PalladiumCatalyzed Sulfinylzincation. Sulfinyl anion is an important reaction intermediate to synthesize various sulfinyl compounds. We have firstly found that sulfinylzinc species can be generated upon treatment of 1 alkynyl suifoxides with Et_2Zn in the presence of Pd(0) catalyst (Org. Lett., 2001, 3, 3627). Owing to its easy generation under the very mild reaction conditions, this methodology enable to synthesize various functionalized vinylic suifoxides stereoselectively(3) Synthesis of Amino Allenes by a Novel PalladiumCatalyzed Reaction. Amino allenes have attracted considerable interest in recent years, since they are versatile substrates for constructing various azacycles. We found a general and efficient synthesis of allenes including amino allenes using a palladium(0)/diethylzinc system: treatment of mesylates or trichloroacetates of 2 bromoalk 2 en 1 ols with diethylzinc and a palladium(0) catalyst affords various allenes bearing an aminoalkyl, alkyl, or aryl substituent in good to high yields (J. Org, Chem. 2002, 67, 1359)