Highly enantioselective intramolecular cyclopropanation reactions of N-allylic-N-methyldiazoacetamides catalyzed by chiral dirhodium(II) carboxamidates
Highly enantioselective intramolecular cyclopropanation reactions of N-allylic-N-methyldiazoacetamides catalyzed by chiral dirhodium(II) carboxamidates
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DOI：
10.1021/jo9519219
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发表时间：
1996-03-22
影响因子：
3.6
通讯作者：
Kalinin, AV
中科院分区：
文献类型：
--
作者：
Doyle, MP;Kalinin, AV
代表性的N-烯丙基-N-甲基重氮乙酰胺的催化重氮分解产生相应的分子内环丙烷化产物，产率从好到优，并具有优异的对映体控制。在最简单的情况下，以N-烯丙基-N-甲基重氮乙酰胺为催化剂，用铑（II）四[2-氧代吡咯烷-5（S）-羧酸甲酯] Rh-2（5（S）-MEPY）（4）催化，获得了最高的产率和对映选择性（93% eel.二铑（II）四[甲基2-氧代-1-（3-苯丙酰基）咪唑烷-4（S）-羧酸酯] Rh-2（4S）-MPPIM）（4）是优选的取代的N-烯丙基-N-甲基重氮乙酰胺，从其在分子内环丙烷化反应中获得92- 95%ee（88-95%产率），甚至当催化剂仅以0.1摩尔%使用时，使用N-甲基重氮乙酰胺相对于N-叔丁基重氮乙酰胺与分子内偶极环加成的竞争最小化。
Catalytic diazo decomposition of representative N-allylic-N-methyldiazoacetamides produced the corresponding intramolecular cyclopropanation products in good to excellent yields and with exceptional enantiocontrol. In the simplest case, with N-allyl-N-methyldiazoacetamide, catalysis by dirhodium(II) tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate], Rh-2(5(S)-MEPY)(4), achieved the highest yield and enantioselectivity (93% eel. Dirhodium(II) tetrakis[methyl 2-oxo-1-(3-phenylpropanoyl)imidazolidin-4(S)-carboxylate] Rh-2(4S)-MPPIM)(4), was preferred for substituted N-allylic-N-methyldiazoacetamides from which 92-95% ee's were obtained in intramolecular cyclopropanation reactions (88-95% yields), even when the catalyst was employed in only 0.1 mol %, Competition with intramolecular dipolar cycloaddition was minimized with the use of N-methyldiazoacetamides relative to N-tert-butyldiazoacetamides.