The synthesis and characterisation of N-(1-carbamoyl-1,1-dialkyl-methyl)-(S)-prolinamides and related pyrrolidin-2-yl-4,5-dihydro-1H-imidazol-5-ones as potential enantioselective organocatalysts
作者:Illia Panov、Pavel Drabina、Jiří Hanusek、Miloš Sedlák
DOI:10.1016/j.tetasy.2011.01.018
日期:2011.1
The acylation of substituted 2-aminopropanamides with (2S)-Boc-proline, (2S)-Cbz-proline and (2S)-Bn-proline was used to prepare substituted 1-protected N-(1-carbamoyl-1,1-dialkyl-methyl)-(S)-prolinamides (74–89%), whose subsequent deprotection gave N-(1-carbamoyl-1,1-dialkyl-methyl)-(S)-prolinamides (94–95%). The enantiomerically pure N-(1-carbamoyl-1,1-dialkyl-methyl)-(S)-prolinamides obtained were
取代的2- aminopropanamides与(2所述的酰化小号)-Boc脯氨酸,(2小号)-Cbz脯氨酸和(2小号使用)-Bn脯氨酸以制备取代的1-保护的ñ - (1-氨基甲酰基-1- ,1-二烷基甲基)-(S)-脯氨酰胺(74-89%),随后脱保护得到N-(1-氨基甲酰基-1,1-二烷基甲基)-(S)-脯氨酰胺(94-95%) )。测试得到的对映体纯N-(1-氨基甲酰基-1,1-二烷基甲基)-(S)-脯氨酰胺作为环己酮与4-硝基苯甲醛的醛醇缩合反应的有机催化剂,产率为ee的38%至79% 。最高的对映选择性(89%ee)是通过用N-(1-氨基甲酰基-环戊基)-(S)-脯氨酰胺(甲醇,10%HCl)。在甲醇钠的作用下,将Boc -N-(1-氨基甲酰基-环戊基)-(S)-脯氨酰胺定量环化为2-(1-Boc-吡咯烷-2-基)-1,3-二氮杂螺[4.4]。非1-en-4-one,伴随脯氨酸骨