EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
J Am Chem Soc. 2010 Nov 10;132(44):15550-2. doi: 10.1021/ja1081603.
A chiral copper(II) complex of 3-(2-naphthyl)-l-alanine amide successfully catalyzes the enantioselective 1,3-dipolar cycloaddition reaction of nitrones with propioloylpyrazole and acryloylpyrazole derivatives. The asymmetric environment created by intramolecular π-cation interaction gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective 1,3-dipolar cycloaddition of nitrones with acetylene derivatives. The 1,3-dipolar cycloadducts can be stereoselectively converted to β-lactams via reductive cleavage of the N-O bond using SmI(2).
3-(2-萘基)-l-丙氨酰胺手性铜(II)配合物成功地催化了硝酮与丙酰基吡唑和丙烯酰基吡唑衍生物的对映选择性 1,3-偶极环加成反应。分子内π-阳离子相互作用所产生的不对称环境以高收率和优异的对映选择性得到相应的加合物。这是硝酮与乙炔衍生物催化对映选择性 1,3-偶极环加成的首例成功方法。1,3-偶极环加成物可以通过使用 SmI(2)还原裂解 N-O 键立体选择性地转化为β-内酰胺。
