Selective transformation of nitriles into amides and carboxylic acids by an immobilized nitrilase
作者:Norbert Klempier、Anna de Raadt、Kurt Faber、Herfried Griengl
DOI:10.1016/s0040-4039(00)92623-6
日期:1991.1
Using an immobilized nitrilase from Rhodococcus sp. mild and selective hydrolysis of nitriles can be achieved even in the presence of acid or base sensitive groups under neutral conditions. This method is applicable to a broad range of substrates as exemplified by aliphatic, alicyclic, heterocyclic and carbohydrate type nitriles.
An aldol-type reaction of organonitriles with aldehydes was catalyzed by a RhI(OR) species underambientconditions, and the reaction displayed a broad substrate scope with respect to both organonitrile and aldehyde components.
Regiospecific opening of 1,2-expoxides with acetone cyanohydrin under mildly basic conditions
作者:David Mitchell、Thomas M Koenig
DOI:10.1016/s0040-4039(00)92067-7
日期:1992.6
Acetone cyanohydrin with stoichiometic triethylamine opens epoxides regiospecifically to give β-hydroxy nitriles. As expected, addition of cyanide occurs at the least substituted carbon.
Biocatalytic asymmetric ring-opening of dihydroisoxazoles: a cyanide-free route to complementary enantiomers of β-hydroxy nitriles from olefins
作者:Daijun Zheng、Yasuhisa Asano
DOI:10.1039/d0gc01445a
日期:——
the cyanide-free synthesis of chiral nitriles and the Kemp elimination reaction catalyzed by aldoxime dehydratases, we herein report a new application of aldoxime dehydratase in the asymmetric ring-opening of 5-sub-4,5-dihydroisoxazoles to synthesize chiral β-hydroxy nitriles with broad substrate scope, excellent enantioselectivity (up to 99% ee), and good turnover number (up to 11 s−1). Upon simple
通过手性腈的无氰化物合成和醛肟脱水酶催化的坎普消除反应的结合,我们在此报道醛肟脱水酶在5-sub-4,5-二氢异恶唑的不对称开环中合成手性β的新应用-羟基腈,具有广泛的底物范围,出色的对映选择性(高达99%ee)和良好的周转率(高达11 s -1)。简单分离并用碱性试剂处理后,剩余的手性5-sub-4,5-二氢异恶唑可轻松转化为它们相应的β-羟基腈。使用定点诱变,证实了含亚铁血红素的活性位点,并提出了两种可能的去质子化途径。据我们所知,这是第一个用于从一个简单的烯烃一步一步构建手性羟基和腈基的酶促反应,这为合成β-羟基互补对映异构体提供了一种新颖而有用的策略腈。
Rhodium to the rescue: The formal aldol products of carboxamides (CONH2) were obtained by using a RhI(OR) (R=H, Me) catalyst under essentially neutral pH and ambient conditions. This novel aldol strategy is based on the catalytic aldol‐type reaction of nitriles, followed by hydration of the nitrile functionality (R1=aromatic or aliphatic, R2 and R3=H or alkyl; see scheme).