Platinum-Catalyzed Hydrosilylations of Internal Alkynes: Harnessing Substituent Effects to Achieve High Regioselectivity
作者:Douglas A. Rooke、Eric M. Ferreira
DOI:10.1002/anie.201108714
日期:2012.3.26
Rule of thumb: The high yielding title reaction is described with a focus on understanding the factors that govern the regioselectivity of the process (see scheme). Electronic, steric, and functional group properties all influence the selectivity, an understanding of which allows the selective formation of trisubstituted vinylsilanes, which are synthetically useful compounds for accessing stereodefined
Convenient Synthesis of 4-Methylene-2-oxazolidinones and 4-Methylenetetrahydro-1,3-oxazin-2-ones via Transition-Metal Catalyzed Intramolecular Addition of Nitrogen Atom to Acetylenic Triple Bond
作者:Yoshinao Tamaru、Masanari Kimura、Shuji Tanaka、Sigeru Kure、Zen-ichi Yoshida
DOI:10.1246/bcsj.67.2838
日期:1994.10
2-Propynyl tosylcarbamates 1 undergo cyclization smoothly by the catalysis of CuCl/Et3N or AgNCO/Et3N to furnish 4-methylene-2-oxazolidinones 2 in good yields. The similar cyclization of the N-acyl derivatives of 1 (PhCO, MeCO, EtOCO, etc.) is catalyzed effectively by AgNCO/t-BuOK. These reactions accommodate a variety of substituents at C1 and C3 of 2-propyn-1-ol and provide (Z)-2 as single stereoisomers. The scope of the cyclization of 3-butynyl carbamates is rather limited, and in general only N-tosyl derivatives of terminally unsubstituted 3-butyn-1-ols undergo cyclization to give 4-methylenetetrahydro-1,3-oxazin-2-ones in synthetically useful yields by the catalysis of AgNCO/Et3N or AgNCO/t-BuOK.
Catalytic (3+2) Palladium‐Aminoallyl Cycloaddition with Conjugated Dienes
作者:Barry M. Trost、Zhongxing Huang
DOI:10.1002/anie.201900693
日期:2019.5.6
application of tailored aminoallyl precursors for catalytic (3+2) cycloaddition with conjugateddienes via a Pd‐aminoallyl intermediate. The new cycloaddition reactions override the conventional (4+3) selectivity of aminoallyl cation cycloaddition through a sequence of Pd‐allyl transfer and ring closure. A variety of highly substituted or fused pyrrolidine rings were synthesized using the cycloaddition, and can
An analysis of the influences dictating regioselectivity in platinum-catalyzed hydrosilylations of internal alkynes
作者:Douglas A. Rooke、Zachary A. Menard、Eric M. Ferreira
DOI:10.1016/j.tet.2014.03.012
日期:2014.7
A full account of our studies on internal alkyne hydrosilylations using platinum catalysis is described. We demonstrate that these transformations are highly governed by the electronic characteristics of the alkyne substituents, wherein the hydride will add preferentially to the more electron-deficient alkyne carbon. The steric and coordinative capabilities of the substituents influence the selectivity
完整介绍了我们对使用铂催化的内部炔烃氢甲硅烷基化的研究。我们证明,这些转变高度受炔烃取代基的电子特性支配,其中氢化物将优先添加至电子欠缺的炔烃碳上。取代基的空间和配位能力对选择性的影响程度要小得多,其中丙炔醇是唯一的例外。硅烷的选择在某些情况下是相关的。特定的硅烷将提供较高的区域选择性,而其他的则选择性要低得多。最终,使用13 C NMR化学位移数据可以完全预测加成的区域选择性,从而将这种反应性纳入目标反应设计中。
Stannylcupration of γ-heterosubstituted acetylenic esters: A new route to 4-stannylated five membered N- and O- heterocycles
4-Tributylstannyl,2-(5H)-furanone and pyrrolone have been prepared in good yields by addition of mixed stannylcuprate reagent on γ-amino and γ-hydroxy acetylenic esters. The use of these compounds as useful intermediates for the selective functionalization of these heterocyclic rings is discussed.