Aza-Darzens asymmetric synthesis of N-(p-toluenesulfinyl) aziridine 2-carboxylate esters from sulfinimines (N-sulfinyl imines)
Aza-Darzens asymmetric synthesis of N-(p-toluenesulfinyl) aziridine 2-carboxylate esters from sulfinimines (N-sulfinyl imines)
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DOI：
10.1021/jo990907j
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发表时间：
1999-10-01
影响因子：
3.6
通讯作者：
Zhang, YL
中科院分区：
文献类型：
--
作者：
Davis, FA;Liu, H;Zhang, YL
The one-step aza-Darzens reaction of sulfinimines 2 with lithium alpha-bromoenolates readily affords diversely substituted cis and trans N-sulfinylaziridine 2-carboxylate esters 3 and 7 in good yield and excellent diastereoselectivity. Higher yields, but lower de's, result when a mixture of the alpha-bromo ester and 2 are treated with base. The N-sulfinyl group is transformed, nearly quantitatively, without ring opening, into the N-tosyl activating group by oxidation with m-CPBA. Selective removal of the N-sulfinyl group in aziridines 3a and 3h with TFA/H2O affords VI-aziridines 21 which are difficult to prepared by other means. However, C(3) activated azirines such as 3b undergo ring-opening under these conditions. Alternatively, the N-sulfinyl group, even in C(3)-activated aziridines, was selectively and efficiently removed by treatment of the aziridine with 2 equiv of MeMgBr.
