Four new chiral aminodiols 1-4, which were prepared from methyl L proline in 2 steps, were applied in the enantioselective addition of diethylzinc to benzaldehyde. The results indicated that the enantioselectivities e...Four new chiral aminodiols 1-4, which were prepared from methyl L proline in 2 steps, were applied in the enantioselective addition of diethylzinc to benzaldehyde. The results indicated that the enantioselectivities enhance with increasing the bulkiness of substituents on chiral ligands and with chiral ligand 4 giving the best result. When ligand 4 was used to catalyze the enantioselective addition of diethylzinc to aromatic aldehydes, the substituents affect the enantioselectivities slightly and 1 naphthaldehyde gives the best enantiomeric excess(up to 75.3% ). On the other hand, 4 (dimethylamino)benzaldehyde gives a low enantiomeric excess, which may most likely arise from a non steroselective ethyl transfer to aldehyde promoted by zinc coordination of amino group. For aliphatic aldehydes, poor enantiomeric excesses are generally given.展开更多
含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环...含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环化串联反应。筛选出最佳的催化剂体系为:10 mol%金鸡纳碱衍生物催化剂1f,二氯甲烷(1 m L)为溶剂,室温反应。将最佳条件用于不同取代靛红的反应,以80~88%的产率和最高达96%的对映选择性获得了螺[羟吲哚-3,4′-吡喃色烯]化合物。本研究拓宽了该反应的催化剂类型和底物范围。展开更多
文摘Four new chiral aminodiols 1-4, which were prepared from methyl L proline in 2 steps, were applied in the enantioselective addition of diethylzinc to benzaldehyde. The results indicated that the enantioselectivities enhance with increasing the bulkiness of substituents on chiral ligands and with chiral ligand 4 giving the best result. When ligand 4 was used to catalyze the enantioselective addition of diethylzinc to aromatic aldehydes, the substituents affect the enantioselectivities slightly and 1 naphthaldehyde gives the best enantiomeric excess(up to 75.3% ). On the other hand, 4 (dimethylamino)benzaldehyde gives a low enantiomeric excess, which may most likely arise from a non steroselective ethyl transfer to aldehyde promoted by zinc coordination of amino group. For aliphatic aldehydes, poor enantiomeric excesses are generally given.
文摘含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环化串联反应。筛选出最佳的催化剂体系为:10 mol%金鸡纳碱衍生物催化剂1f,二氯甲烷(1 m L)为溶剂,室温反应。将最佳条件用于不同取代靛红的反应,以80~88%的产率和最高达96%的对映选择性获得了螺[羟吲哚-3,4′-吡喃色烯]化合物。本研究拓宽了该反应的催化剂类型和底物范围。
