Catalytic, enantioselective α-additions of isocyanides:: Lewis base catalyzed Passerini-type reactions
Catalytic, enantioselective α-additions of isocyanides:: Lewis base catalyzed Passerini-type reactions
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DOI：
10.1021/jo050549m
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发表时间：
2005-11-25
影响因子：
3.6
通讯作者：
Fan, Y
中科院分区：
文献类型：
--
作者：
Denmark, SE;Fan, Y
异氰化物与醛的催化、对映选择性α-加成的一般性已经得到证明（Passerini型反应）。四氯化硅和手性双磷酰胺（R，R）-1b的催化体系为叔丁基异腈与各种醛（芳香族、杂芳香族、烯属、炔属、脂肪族）的加成提供了高产率和良好至优异的对映选择性。水性后处理得到α-羟基叔丁基酰胺，而低温甲醇淬灭，随后碱性后处理得到α-羟基甲酯。该反应对于其他异腈也是成功的，尽管具有降低的对映选择性。发现反应条件，特别是异氰化物的添加速率对于良好的产率和高选择性是至关重要的。
The generality of catalytic, enantioselective alpha-additions of isocyanides to aldehydes has been demonstrated (Passerini-type reactions). The catalytic system of silicon tetrachloride and a chiral bisphosphoramide (R,R)-1b provided high yields and good to excellent enantioselectivities for the addition of tert-butyl isocyanide to a wide range of aldehydes (aromatic, heteroaromatic, olefinic, acetylenic, aliphatic). Aqueous workup afforded the alpha-hydroxy tert-butyl amides whereas a low-temperature methanol quench followed by basic workup afforded the a-hydroxy methyl esters. The reaction is also successful for other isocyanides, albeit with reduced enantioselectivity. Reaction conditions, particularly the rate of addition of the isocyanide was found to be crucial for good yields and high selectivities.