Asymmetric 1,3-Dipolar Cycloaddition Reactions of Nitrile Oxides Catalyzed by Chiral Binaphthyldiimine-Ni(II) Complexes
Asymmetric 1,3-Dipolar Cycloaddition Reactions of Nitrile Oxides Catalyzed by Chiral Binaphthyldiimine-Ni(II) Complexes
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DOI：
10.1021/jo802392c
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发表时间：
2009-02-06
影响因子：
3.6
通讯作者：
Baba, Toshihide
中科院分区：
文献类型：
--
作者：
Suga, Hiroyuki;Adachi, Yuki;Baba, Toshihide
在手性联萘亚胺 (BINIM)-Ni(II) 配合物作为催化剂的情况下，几种腈氧化物与 3-(2-烯酰基)-2-恶唑烷酮和 2-(2-烯酰基)-3-吡唑烷酮衍生物之间进行了不对称环加成反应。使用 (R)-BINIM-4(3,5-二甲苯基)-2QN-Ni(II) 络合物 (30 mol %)，可分离的 2,4,6-三甲基苯甲腈氧化物和 4-Me 加合物之间的反应获得了良好的区域选择性 (4-Me/5-Me = 85:15) 和高对映选择性 (96% ee)。 3-巴豆酰基-5,5-二甲基-2-恶唑烷酮。在MS 4埃存在下由相应的羟肟酰氯产生的取代和未取代的苯甲腈氧化物和脂肪族腈氧化物与3-巴豆酰基-5,5-二甲基-2-恶唑烷酮、5,5-二甲基-3-(2-戊烯酰基)-2-恶唑烷酮反应， 5,5-二甲基-3-[3-(乙氧基羰基)丙烯酰基]-2-恶唑烷酮、1-苄基-2-巴豆酰基-5,5-二甲基-3-吡唑烷酮和1-苄基-2-[3-(乙氧基羰基)丙烯酰基]-5,5-二甲基-3-吡唑烷酮(R)-BINIM-4Ph-2QN-Ni(II) 或 (R)-BINIM-4(3,5-二甲苯基)-2QN-Ni(II) 络合物 (10-30 mol %) 作为催化剂，以高收率、高区域选择性 (4-R/5-R = 85:15-99:1) 和中等到高对映选择性生成相应的环加合物(42-95% ee) 的 4-R 加合物。使用吡唑烷酮衍生物作为亲偶极试剂的反应获得了较高的对映选择性和区域选择性。对于 (R)-BINIM-4(3,5-二甲苯基)-2QN-Ni(II) 络合物 (30 mol%) 催化的 2-(2-烯酰基)-1-苄基-5,5-二甲基-3-吡唑烷酮环加成，对映选择性从 75% 到 95% ee 不等。在 (R)-BlNIM-4(3,5-二甲苯基)-2QN-Ni(II) 络合物 (10 mol %) 存在下，几种腈氧化物与 2-乙酰酰基-1-苄基-5,5-二甲基-3-吡唑烷酮之间的反应产生对映选择性 (79-91 % ee)，超过了之前报道的丙烯酸对映选择性环加成反应衍生物。此外，还使用使用 PM3 计算的分子建模程序进行了研究，以深入了解不对称诱导的机制。
Asymmetric cycloaddition reactions between several nitrile oxides and 3-(2-alkenoyl)-2-oxazolidinones and 2-(2-alkenoyl)-3-pyrazolidinone derivatives were carried out in the presence of chiral binaphthyldiimine (BINIM)-Ni(II) complexes as catalysts. Using (R)-BINIM-4(3,5-xylyl)-2QN-Ni(II) complex (30 mol %), good regioselectivity (4-Me/5-Me = 85:15) along with high enantioselectivity (96% ee) of the 4-Me adduct were obtained for the reaction between isolable 2,4,6-trimethylbenzonitrile oxide and 3-crotonoyl-5,5-dimethyl-2-oxazolidinone. Substituted and unsubstituted benzonitrile oxides and aliphatic nitrile oxides, which were generated from the corresponding hydroximoyl chloride in the presence of MS 4 angstrom, were reacted with 3-crotonoyl-5,5-dimethyl-2-oxazolidinone, 5,5-dimethyl-3-(2-pentenoyl)-2-oxazolidinone, 5,5-dimethy-3-[3-(ethoxycarbonyl)propenoyl]-2-oxazolidinone, 1-benzyl-2-crotonoyl-5,5-dimethyl-3-pyrazolidinone, and 1-benzyl-2-[3-(ethoxycarbonyl)propenoyl]-5,5-dimethy-3-pyrazolidinone in the presence of (R)-BINIM-4Ph-2QN-Ni(II) or (R)-BINIM-4(3,5-xylyl)-2QN-Ni(II) complexes (10-30 mol %) as catalysts to give the corresponding cycloadducts in high yields, with high regioselectively (4-R/5-R = 85:15-99:1) and with moderate to high enantioselectivities (42-95% ee) of the 4-R adducts. Higher enantioselectivities and regioselectivities were obtained for the reactions using pyrazolidinone derivatives as the dipolarophiles. For the cycloadditions of 2-(2-alkenoyl)-1-benzyl-5,5-dimethyl-3-pyrazolidinones catalyzed by (R)-BINIM-4(3,5-xylyl)-2QN-Ni(II) complex (30 mol %), the enantioselectivity varied from 75% to 95% ee. The reactions between several nitrile oxides and 2-actyloyl-1-benzyl-5,5-dimethyl-3-pyrazolidinone in the presence of (R)-BlNIM-4(3,5-xylyl)-2QN-Ni(II) complex (10 mol %) resulted in enantioselectivities (79-91 % ee) that exceed those of previously reported enantioselective cycloadditions of acrylic acid derivatives. Furthermore, studies using a molecular modeling program using PM3 calculations were carried out to gain insight into the mechanisms of the asymmetric induction.