乙醇作为一个olefinic合作伙伴在enyne循环. 一个新的双重循环到立体定义的bicyclo[3.3.0]octenes
Hirokazu Urabe1, Daisuke Suzuki, Misa Sasaki
1Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan. hurabe@bio.titech.ac.jp
Journal of the American Chemical Society
|April 3, 2003
概括
一种新介导的联循环反应有效合成具有高立体选择性的复杂双循环二醇. 这种方法在单个步骤中构建多个立体中心,为有机合成提供了强大的工具.
科学领域:
- 有机化学 有机化学
- 立体选择性合成 立体选择性合成
- 有机金属化学 有机金属化学
背景情况:
- 复杂分子的立体选择合成仍然是有机化学的一个重大挑战.
- 介导反应已经成为构建复杂分子架构的强大工具.
研究的目的:
- 开发一种新的双联循环反应,用于双环[3.3.0]乙烯二醇的立体选择性合成.
- 调查这种新合成方法的普遍性和 diastereoselectivity.
主要方法:
- 用 (II) 氧化剂 (TiO-i-Pr) 4/2i-PrMgCl) 处理 (Z) - 基烯 (Z) - 基烯 (Z) - 基烯 (Z) - 基烯 (Z) - 基烯 (Z) -基烯 (Z) -基烯 (Z) -基 (Z) -基 (Z) -基) -基 (Z) -基 (Z) -基) -基 (Z) -基基 (Z) -基基 (Z) -基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基基
- 用水处理来隔离循环产品.
- 使用光谱方法和二聚体比率分析立体化学结果.
主要成果:
- (Z) -1-三-6-基酸盐的反应产生了 (1RS,2RS,3SR) -3-乙基-4-基-4-双循环[3.3.0]octene-2,3-diol作为单个立体同位素.
- (Z) - 3 - -1-三-6 - 氨基酸盐的反应产生了二聚体纯的双循环二醇,其二聚体选择性>95:5.
- 演示了四个连续立体中心的同时构建,具有高保真度.
结论:
- 开发的以为媒介的联循环是一种高效的方法,用于构建复杂的双循环二醇.
- 这种反应以出色的立体控制进行,在单个合成操作中建立多个立体中心.
- 该方法对立体化学丰富的有机分子的高效合成具有前景.
相关概念视频
Structure and Nomenclature of Epoxides
Cyclic ethers are heterocyclic compounds with an oxygen atom in the ring along with carbon atoms. They are named depending on the number of carbon atoms present in their ring system. Cyclic ethers with a three-membered ring system are called “oxirane”, four-membered ring systems as “oxetane”, five-membered ring systems as “oxolane”, and six-membered ring systems as “oxane”. The cyclic structure of these rings imposes angle strain, and this strain is more in the ring having a smaller number of...
Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.


