Highly selective synthetic organic reaction using cyclopropane ring opening

1)实现了从sp3中心手性到轴向手性的手性交换苄基环化，得到了具有优异对映选择性的轴向手性1-芳基萘。采用手性交换苄环法制备了具有光学活性的原邻苯酞。2)利用Sc(OTf)3或BF3对甲基（芳基羟甲基）-环丙烷羧酸酯进行了新型扩环反应，得到了高产率至优异的1,2-二氢萘-3-羧酸酯。在反应过程中，环丙烷发生了高度区域选择性的开环和序贯环化。以SmI2促进的reformatsky型反应和Sc(OTf)3介导的非星形选择性扩环为关键步骤，证明了环galgravin及其二羧基类似物的全合成。该方法包括将宝石-二氯环丙烷的两个C-Cl键转化为两个C-C键。

1) We achieved the chirality exchange benzannulation from sp3 central chirality to axial chirality, and obtained axially chiral 1-arylnaphthalenes with excellent enantioselectivity. Total synthesis of optically active Procunphthalide was demonstrated by using the chirality exchange benzannulation. 2) A novel ring-expansion of methyl (arylhydroxymethyl)- cyclopropanecarboxylates using Sc(OTf)3 or BF3 afforded 1,2-dihydronaphthalene-3-carboxylic acid ester in high to excellent yields. In the reaction, highly regioselective ring opening of cyclopropane and sequential cyclization occurred. Total synthesis of cyclogalgravin and its dicarboxyl analog was demonstrated by using the SmI2- promoted Reformatsky-type reaction and the Sc(OTf)3-mediated diasteroselective ring expansion as key steps. This method includes a novel transformation of two C-Cl bonds of gem- dichlolocyclopropane to two C-C bonds.