Synergistic Catalysis by Brønsted Acid/Carbodicarbene Mimicking Frustrated Lewis Pair‐Like Reactivity
作者:Yi‐Chen Chan、Yuna Bai、Wen‐Ching Chen、Hsing‐Yin Chen、Chen‐Yu Li、Ying‐Yann Wu、Mei‐Chun Tseng、Glenn P. A. Yap、Lili Zhao、Hsuan‐Ying Chen、Tiow‐Gan Ong
DOI:10.1002/anie.202107127
日期:2021.9
Carbodicarbene (CDC), unique carbenic entities bearing two lone pairs of electrons are well-known for their strong Lewis basicity. We demonstrate herein, upon introducing a weak Brønstedacid benzyl alcohol (BnOH) as a co-modulator, CDC is remolded into a Frustrated Lewis Pair (FLP)-like reactivity. DFT calculation and experimental evidence show BnOH loosely interacting with the binding pocket of CDC
The trimerization of phenyl isocyanate in the presence of triethylamine was accelerated under high pressure to give triphenyl isocyanurate almost quantitatively. The reaction in benzene was remarkably accelerated by compression. The effects of pressure, temperature, catalysts, and solvents were examined on the trimerization of phenyl isocyanate. Aryl and normal alkyl isocyanatestrimerized under high
An Electron-Rich Proazaphosphatrane for Isocyanate Trimerization to Isocyanurates
作者:Steven M. Raders、John G. Verkade
DOI:10.1021/jo9023396
日期:2010.8.6
synthesis of the new electron-rich, sterically hindered proazaphosphatrane shown above is described herein. This proazaphosphatrane catalyzes the cyclotrimerization of a wide variety of isocyanates to isocyanurates under mild conditions with unprecedentedly fast reaction times, giving moderate to high product yields. It is also shown that this proazaphosphatrane can be recycled up to 5 times.
First Synthesis of a Highly Basic Dendrimer and its Catalytic Application in Organic Methodology
作者:Arunkanti Sarkar、Palanichamy Ilankumaran、Philip Kisanga、John G. Verkade
DOI:10.1002/adsc.200404089
日期:2004.8
Sixteen OCH2CH2N3P(i-BuNCH2CH2)3N substituents (A) containing the highly basic bicyclic azido-phosphine moiety shown, have been incorporated into the dendrimer [CH2CH2N[(CH2)3N[(CH2)3NHC(O)-3,5-bis-(A)-C6H3]2]2]2 in five steps from commercially available starting materials with an overall yield of 22.5%. Also presented are examples of Michael additions, nitroaldol reactions and aryl isocyanate trimerizations
已将包含所示的高度碱性双环叠氮基膦部分的16个OCH 2 CH 2 N 3 P(i -BuNCH 2 CH 2)3 N取代基(A)引入树枝状聚合物[CH 2 CH 2 N [(CH 2)3 N [(CH 2)3 NHC(O)-3,5-双-(A)-C 6 H 3 ] 2 ] 2 ] 2从市售原料中分五个步骤完成,总收率为22.5%。还提供了由树状大分子有效催化的迈克尔加成反应,硝基缩醛反应和芳基异氰酸酯三聚反应的例子。
Cyclic tetramers of a five-membered palladacycle based on a head-to-tail-linked isocyanate dimer and their reactivity in cyclotrimerization of isocyanates
作者:Seon Gye Lee、Keun-Young Choi、Yong-Joo Kim、SuJin Park、Soon W. Lee
DOI:10.1039/c5dt00534e
日期:——
Reactions of [Pd(styrene)(PR3)2], generated from trans-[PdEt2(PR3)2] and styrene, with 2 equiv. of benzyl isocyanate in THF at room-temperature afforded unusual cyclic Pd-tetramers of five-membered rings consisting of organic isocyanatedimers and palladium, [Pd(PR3)–C(O)N(R)C(O)N(R)–}]4 (PR3 = PMe3, 1; PR3 = PMe2Ph, 2). Additionally, a cyclic trimer, (RNCO)3, 3 (R = benzyl) was produced as a catalytic