Novel Carbonyl Allylation Mediated by SnCl2/TiCl3 in Water
摘要:
Under the Lewis acid catalysis offered by TiCl3, SnCl2 can efficiently mediate the aqueous Barbier reactions between aldehydes and allyl chloride or bromide.
Allylic gallium reagents, prepared from gallium trichloride and the corresponding allylic Grignard reagents, allylated carbonyl compounds in good yields in an aqueous medium as well as in organic solvent.
A Convergent Coupling Strategy for the Formation of Polycyclic Ethers: Stereoselective Synthesis of the BCDE Fragment of Brevetoxin A
作者:Michael T. Crimmins、Patrick J. McDougall、Kyle A. Emmitte
DOI:10.1021/ol051543m
日期:2005.9.1
has been completed. anti-Glycolate aldol, glycolate alkylation, and ring-closing metathesis reactions were employed as key bond-forming events. A convergent assembly strategy was employed that relied on a Horner-Wadsworth-Emmons union of two complex fragments. Subsequent cyclization and dehydration led to efficient generation of an intermediate endocyclic enolether, which was advanced to a tetracyclic
Stereoselective Synthesis of Quaternary Carbons via the Dianionic Ireland–Claisen Rearrangement
作者:Michael T. Crimmins、John D. Knight、Philip S. Williams、Yan Zhang
DOI:10.1021/ol5008422
日期:2014.5.2
α-methyl-β-hydroxy allylic esters has been developed that proceeds with high diastereoselectivity and provides products containing three contiguous stereogenic carbons, including a quaternary center. The potential utility of the rearrangement for complex molecule synthesis is also demonstrated.
Selective allylation of carbonyl compounds in aqueous media
作者:Cathy Einhorn、Jean-Louis Luche
DOI:10.1016/0022-328x(87)85005-2
日期:1987.3
The use of aqueous neutral media leads to excellent yields of homoallylic alcohols from reaction sof allyl halides with carbonyl compounds in the presence of tin or zinc. The stereochemicalcourse and range of application of this reaction have been investigated.
Enantioselective Total Synthesis of Brevetoxin A: Unified Strategy for the B, E, G, and J Subunits
作者:Michael T. Crimmins、J. Michael Ellis、Kyle A. Emmitte、Pamela A. Haile、Patrick J. McDougall、Jonathan D. Parrish、J. Lucas Zuccarello
DOI:10.1002/chem.200900776
日期:2009.9.14
oxacycles, as well as 22 tetrahedral stereocenters. Herein, we describe a unified approach to the B, E, G, and J rings based upon a ring‐closing metathesis strategy from the corresponding dienes. The enolate technologies developed in our laboratory allowed access to the precursor acyclic dienes for the B, E, and G medium‐ring ethers. The strategies developed for the syntheses of these four monocycles
Brevetoxin A 是一种十环梯形毒素,具有 5、6、7、8 和 9 元氧杂环,以及 22 个四面体立体中心。在此,我们描述了基于来自相应二烯的闭环复分解策略的 B、E、G 和 J 环的统一方法。我们实验室开发的烯醇技术允许获得 B、E 和 G 中环醚的前体无环二烯。为合成这四个单环而开发的策略最终提供了数克数量的每个环,支持我们为完成短毒素 A 的收敛合成所做的努力。