Asymmetric formal synthesis of (-)-pancracine via catalytic enantioselective C-H amination process
Asymmetric formal synthesis of (-)-pancracine via catalytic enantioselective C-H amination process
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DOI：
10.1016/j.tet.2008.10.091
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发表时间：
2009-04-18
期刊：
影响因子：
2.1
通讯作者：
Hashimoto, Shunichi
中科院分区：
文献类型：
--
作者：
Anada, Masahiro;Tanaka, Masahiko;Hashimoto, Shunichi
环己酮衍生的硅基冷醚与1-（4-硝基苯磺酰基）亚氨基的反应|四[N-四氯邻苯二甲酰基-（S）-叔-亮氨酸] Rh-2（S-TCPTTL）（4）二铑（II）催化的苯基碘烷（pNsN=IPh）在脱甲硅烷基后在Lip中提供N-pNs-保护的（S）-β-氨基环己酮，达到72%ee。利用这一过程，一个新的催化不对称路线的高级中间体在Overman的合成montanine型石蒜科生物碱（-）-pancracine已开发。关键步骤包括（a）一锅Rh-2（R-TCPTTI_）（4）-催化的2-环己烯-1-酮的顺序1，4-氢化硅烷化/对映选择性C-H胺化，（B）N-烷基化和随后的分子内Mukaiyama羟醛缩合反应/脱水，和（c）双环烯酮27的区域和空间控制的还原脱氧，双键迁移，产生C1/C2-C3-C4-C C11 a双键和3-芳基六氢吲哚的Cl I处的立体异构中心31。(C)2008年爱思唯尔有限公司。好的。reserved.
The reaction of silyl cool ethers derived from cyclohexanone with 1(4-nitropheylsulfonyl)imino|phenyliodinane (pNsN=IPh) catalyzed by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate] Rh-2(S-TCPTTL)(4), provides, after desilylation, N-pNs-protected (S)-beta-aminocyclohexanone in Lip to 72% ee. This represents the first example of the insertion of nitrene species into ail allylic C-H bond of silyl enol ethers. Using this process, a new catalytic asymmetric route to an advanced intermediate in Overman's synthesis of the montanine-type Amaryllidaceae alkaloid (-)-pancracine has been developed. The key steps involve (a) a one-pot Rh-2(R-TCPTTI_)(4)-catalyzed sequential 1,4-hhydrosilylation/enantio-selective C-H amination of 2-cyclohexen-1-one, (b) N-alkylation and subsequent intramolecular Mukaiyama aldol reaction/dehydration, and (c) a regio- and steieocontrolled reductive deoxygenation of bicyclic enone 27 with migration of the double bond to create the C1/C11a double bond and the stereogenic center at Cl I of 3-arylhexahydroindole 31. (C) 2008 Elsevier Ltd. All right,. reserved.