R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with P...R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with PhCH 2Br to form the N-Boc-(4R)-benzyloxy-(S)-proline, which, after removal of the protecting group with CF 3COOH gave the title compound. As an efficient catalyst for the direct asymmetryic aldol reaction the compound gave products in yield ranged from 58% to 77% with enantiomeric excess up to 88%.展开更多
以(S)-脯氨酸1为原料,在酸性条件和金属锌的催化还原作用下,通过与甲醛反应,高收率获得了(S)-N-甲基脯氨酸2。然后在N,N-二甲基乙酰胺(DMAc)和CH_2Cl_2体系中,(S)-N-甲基脯氨酸2与SOCl_2在0℃下反应20min,制得的酰氯不经提纯直接与加入...以(S)-脯氨酸1为原料,在酸性条件和金属锌的催化还原作用下,通过与甲醛反应,高收率获得了(S)-N-甲基脯氨酸2。然后在N,N-二甲基乙酰胺(DMAc)和CH_2Cl_2体系中,(S)-N-甲基脯氨酸2与SOCl_2在0℃下反应20min,制得的酰氯不经提纯直接与加入的甲醇在25℃下反应5h,获得中间产物(S)-N-甲基脯氨酸甲酯3。最后以LiAlH_4为还原剂,四氢呋喃为溶剂,高收率(87.3%)地获得了(S)-N-甲基脯氨醇4。产物结构经~1 H NMR、^(13)C NMR、HRMS确证。展开更多
文摘R)-Hydroxy-(S)-proline was N-protected by reaction with di-tert-butyl pyrocarbonate to give N-Boc-(4R)-hydroxy-(S)-proline, which was treated with NaH in anhydrous tetrahydrofuran and followed by etherification with PhCH 2Br to form the N-Boc-(4R)-benzyloxy-(S)-proline, which, after removal of the protecting group with CF 3COOH gave the title compound. As an efficient catalyst for the direct asymmetryic aldol reaction the compound gave products in yield ranged from 58% to 77% with enantiomeric excess up to 88%.
文摘以(S)-脯氨酸1为原料,在酸性条件和金属锌的催化还原作用下,通过与甲醛反应,高收率获得了(S)-N-甲基脯氨酸2。然后在N,N-二甲基乙酰胺(DMAc)和CH_2Cl_2体系中,(S)-N-甲基脯氨酸2与SOCl_2在0℃下反应20min,制得的酰氯不经提纯直接与加入的甲醇在25℃下反应5h,获得中间产物(S)-N-甲基脯氨酸甲酯3。最后以LiAlH_4为还原剂,四氢呋喃为溶剂,高收率(87.3%)地获得了(S)-N-甲基脯氨醇4。产物结构经~1 H NMR、^(13)C NMR、HRMS确证。
