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苯环反应，得到了具有良好对映体选择性的轴向手性1-芳基萘。通过手性交换苯环反应，证明了旋光性原苯妥英的全合成。2)用Sc(OTf)_3或BF_3对(芳基羟甲基)-环丙烷羧酸甲酯进行扩环反应，高产率地合成了1，2-二氢-3-萘甲酸酯。在反应中，发生了环丙烷的高区域选择性开环和顺序环化反应。以SmI2促进的Reformsky反应和Sc(OTf)3介导的非对映选择性扩环反应为关键步骤，实现了环加尔格雷文及其二羧基类似物的全合成。该方法包括将GEM-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.