Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles

Abstract

For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.

Multicomponent Porphyrin‐Based Tetragonal Prismatic Metallacages and their Photophysical Properties

“…All reagents were purchased from commercially available suppliers and used without further purification. Compound 3 c was prepared according to a procedure reported in literature . NMR spectra were recorded on a Varian Unity 300 MHz or Bruker 400 MHz spectrometer.…”

“…Compound 3 c was prepared according to a procedure reported in literature. [20] NMR spectra were recorded on a Varian Unity 300 MHz or Bruker 400 MHz spectrometer. 1 H NMR chemical shifts are reported relative to residual solvent signals, and 31 P{ 1 H} NMR chemical shifts are referenced to an external unlocked sample of 85 % H 3 PO 4 (d = 0.0).…”

Alquinos calcogênicos: Síntese e aplicações em reações multicomponentes para a obtenção de núcleos quinolínico, propargilaminas e ésteres vinil β-borilados

“…Rev. 2011, 40, 4893. Inicialmente, foi utilizado o AgNTf2 como catalisador em DCM a 45 ºC como descrito na literatura por Zhu e colaboradores, 60 e o produto 15a foi obtido em 54% de rendimento. Sendo assim, foi testada uma série de ácidos de Lewis como catalisadores, tais como: In(OTf)3, Sc(OTf)2, Cu(OTf)2, Yb(OTf)3, AuCl3 e FeCl3 (Tabela 7, entradas 2-7).…”

“…Os rendimentos são inferiores se comparados aos alquinos calcogênicos contendo selênio, como já mencionado anteriormente, pelo fato de que o telúrio é um átomo que possui um raio atômico maior que o selênio, ocorrendo um impedimento no carbono ligado a esse átomo dificultando desse modo a formação do produto. 60 Zhang, X.; Liu, Baoqing, L.; Shu, X.; Gao, Y.; Lv, H.; Zhu, J. J. Org.…”

“…IV υmax (cm -1 ): 3255,2833,2758,2045,1555,1460,1393,1203,1203,1000,715,668. (75 MHz,CDCl3) δ 159,0;135,0;134,1;129,7;129,1;129,1;128,9;127,9;114,0;95,6;79,3;71,3;60,8;55,3;52,2;25,7;24,4;24,1 ppm. EMAR calculado para C25H29NO2Se (ESI-TOF, [M -C5H10N] + ): 371,0553.…”