催化碳化螺旋乳酸化
Dexter C Davis1, Katherine L Walker2, Chunhua Hu3
1Department of Chemistry and Center for Cancer Research, Purdue University , West Lafayette, Indiana 47907, United States.
Journal of the American Chemical Society
|July 27, 2016
概括
一种新的催化方法有效合成天然产品中存在的有价值的化合物. 这种可扩展的反应提供了温和的条件和广泛的范围,有助于药物发现和合成.
科学领域:
- 有机化学
- 催化剂
- 自然产品合成
背景情况:
- 在许多具有显著治疗潜力的复杂天然产品中,氧化素是普遍存在的结构动图.
- 这些有价值的化合物的有效合成途径对于药物发现和开发至关重要.
- 现有的方法可能缺乏复杂分子合成所需的效率,范围或温和性.
研究的目的:
- 开发一种新的催化级联碳化螺旋乳化反应.
- 建立一个高效和可扩展的合成oxaspirolactones的方法.
- 在复杂的自然产品的总合成中证明这种方法的实用性.
主要方法:
- 催化级联碳酸性螺旋乳酸化.
- 库林科维奇反应用于制备氧cyclopropanol基质.
- 使用开发的方法进行自然产品的总合成.
- 使用高分辨率电喷射电离质谱 (ESI-MS) 的机制研究.
主要成果:
- 开发的方法在温和的反应条件下有效合成氧化.
- 证明了高原子经济性,广泛的基板范围和可扩展性.
- 土耳其烟草天然产品α-levantanolide和α-levantenolide的整体合成分别在两个和四个步骤中实现.
- 机理学研究阐明了关键的中间体,并确定了催化剂分解途径.
结论:
- 一种新且高效的催化级联碳酸性螺旋乳化已经确立.
- 这种方法提供了一种可扩展和多用途的方法来获得oxaspirolactones和相关的天然产品.
- 这些发现有助于复杂治疗化合物的合成策略的发展.
相关概念视频
01:57Preparation of Diols and Pinacol Rearrangement
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Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
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03:08Hydroboration-Oxidation of Alkenes
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In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
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02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
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Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
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01:27Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
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Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
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03:00Preparation of Epoxides
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Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
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02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
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Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
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