Synthesis of enantiomerically pure N-tert-butanesulfinyl imines (tert-butanesulfinimines) by the direct condensation of tert-butanesulfinamide with aldehydes and ketones
Synthesis of enantiomerically pure N-tert-butanesulfinyl imines (tert-butanesulfinimines) by the direct condensation of tert-butanesulfinamide with aldehydes and ketones
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DOI：
10.1021/jo982059i
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发表时间：
1999-02-19
影响因子：
3.6
通讯作者：
Ellman, JA
中科院分区：
文献类型：
--
作者：
Liu, GC;Cogan, DA;Ellman, JA
描述了从醛和酮一步制备n -叔丁烷磺酰亚胺（叔丁烷磺酰亚胺）(2)的第一种一般方法的实验细节。为了影响叔丁烷磺酰胺(1)与醛的缩合作用，采用了Lewis酸性脱水剂MgSO4、CuSO4或Ti(OEt)(4)。当过量的醛被使用时，由MgSO4介导的醛缩合反应以高收率（84-96%）进行。相比之下，当使用较多的刘易斯酸性脱水剂CuSO4时，只需要少量过量的乙醛（1.1当量）相对于叔丁烷亚胺就能提供高产量的亚亚胺。cuso4介导的过程对多种醛有效，包括要求立体的醛，如异丁醛（90%）和富含电子的醛，如对茴香醛（81%）。刘易斯酸性更强的Ti(OEt)(4)和Ti(O-i-Pr)(4)也能从非活性醛（如戊醛（82%））中产生n -叔丁烷磺酸基醛胺。此外，Ti(OEt)(4)对I与酮类的缩合反应是有效的，可以得到大范围的n -叔丁烷磺酸基酮胺，收率高（77-91%）。对于由甲基或正烷基苯基酮和甲基或正烷基异丙基酮衍生的亚砜基酮胺，CDCl3中的H-1和C-13 NMR仅检测到E异构体。对于那些对亚胺的空间需求差异很小的情况，例如对2-己酮，仍然观察到高E/Z比（5:1）。
Experimental details for the first general methods for the one-step preparation of N-tert-butanesulfinyl imines (tert-butanesulfinimines) (2) from aldehydes and ketones is described. To effect the condensations of tert-butanesulfinamide (1) with aldehydes, the Lewis acidic dehydrating agents MgSO4, CuSO4, or Ti(OEt)(4) are employed. Aldehyde condensations mediated by MgSO4 proceed in high yields (84-96%) when an excess of aldehyde is used. In contrast, only a slight excess of aldehyde (1.1 equiv) relative to tert-butanesulfinamide provides sulfinimines in high yields when the more Lewis acidic dehydrating agent CuSO4 is used. The CuSO4-mediated procedure is effective for a wide range of aldehydes, including sterically demanding aldehydes, such as isobutyraldehyde (90%), and electron-rich aldehydes, such as p-anisaldehyde (81%). The still more Lewis acidic Ti(OEt)(4) and Ti(O-i-Pr)(4) also afford N-tert-butanesulfinyl aldimines from especially unreactive aldehydes, such as pivaldehyde (82%). In addition, Ti(OEt)(4) is effective for the condensation of I with ketones to afford a wide range of N-tert-butanesulfinyl ketimines in good yields (77-91%). For sulfinyl ketimines derived from methyl or n-alkyl phenyl ketones and methyl or n-alkyl isopropyl ketones, only the E isomer is detected by H-1 and C-13 NMR in CDCl3. For those cases where the difference in steric demand about the imine is very small, such as for 2-hexanone, high E/Z ratios are still observed (5:1).