Grzegorz Hreczycho

New One-Pot Synthesis of (E)-β-Aryl Vinyl Halides from Styrenes

A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-beta-aryl vinyl iodides and (E)-beta-aryl vinyl bromides from styrenes based on sequential ruthenium-catalyzed silylative coupling-N-halosuccinimide-mediated halodesilylation reactions is reported.

(E)-9-(2-iodovinyl)-9H-carbazole: a new coupling reagent for the synthesis of π-conjugated carbazoles.

The one-pot synthesis of (E)-9-(2-iodovinyl)-9H-carbazole via sequential ruthenium-catalyzed silylative coupling of N-vinylcarbazole with vinyltrimethylsilane and iododesilylation is reported. Its use as a new building block in the palladium-catalyzed Sonogashira and Suzuki-Miyaura coupling reactions to yield new carbazole-containing (E)-but-1-en-3-ynes and (E,E)-buta-1,3-dienes is demonstrated.

A new selective approach to unsymmetrical siloxanes and germasiloxanes via O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes

A scandium(III) trifluoromethanesulfonate-catalyzed O-metalation of silanols with 2-methylallylsilanes and 2-methylallylgermanes leading to siloxane or germasiloxane bond formation under mild conditions with evolution of isobutylene is described.

One-pot synthesis of (E)-styryl ketones from styrenes.

A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-styryl ketones from styrenes based on sequential ruthenium-catalyzed silylative coupling-rhodium-catalyzed desilylative acylation reactions is reported.

Highly Efficient Catalytic Route for the Synthesis of Functionalized Silsesquioxanes

Silsesquioxanes (POSS) have recently become the subject of growing interest in many branches of materials chemistry. Despite this great interest, no direct metal-catalyzed method to cap the corner of the POSS molecules has yet been proposed. In this report, we present a highly efficient method for the synthesis of functionalized silsesquioxanes mediated by scandium(III) triflate, which opens up the possibility of introducing a wide variety of functional groups into this class of organosilicon compounds under mild conditions with excellent yields. We also investigated the differences in the activity of the Lewis acid (Sc(OTf)3) and the hidden Brønsted acid (TfOH) generated in situ from triflates as catalysts in the functionalization of silsesquioxanes. What is more, this solution provides an efficient corner-capping reaction and other functionalizations to obtain silsesquioxane derivatives which are often not possible to synthesize with good yields, efficiency, and chemoselectivity using conventional methods.

Ruthenium-catalyzed silylation of 1,3-butadienes with vinylsilanes.

A novel method for the synthesis of 1-silyl-substituted 1,3-butadienes, based on [RuHCl(CO)(PCy3)2]-catalyzed silylative coupling of terminal (E)-1,3-dienes with vinylsilanes, is reported. The reaction provides a facile and straightforward access to (E,E)-dienylsilanes in a highly stereoselective fashion (especially for aryl-substituted dienes) and opens a valuable and general synthetic route for the direct catalytic silylation of conjugated dienes with elimination of ethylene as a single byproduct. Preliminary results on synthetic application of the synthesized silylated 1,3-butadienes in desilylation reactions are described.

Highly Selective Hydrothiolation of Unsaturated Organosilicon Compounds Catalyzed by Scandium(III) Triflate

The first use of a Lewis acid catalyst in the addition reaction of both aromatic and aliphatic thiols to unsaturated organosilicon compounds is reported. In catalytic tests, scandium(III) triflate demonstrates high catalytic activity in this process. Under mild conditions (25 °C, room temperature, 1-10 h) a number of thioether-functionalized organosilicon species are obtained with appreciable selectivity. This study constitutes the first example of allylsilane hydrothiolation that gives the Markovnikov regioisomer as the main product. Ethynylsilanes are also successfully used in the hydrothiolation reaction in the presence of Sc(OTf)3 .

Catalytic Formation of Silicon-Heteroatom (N, P, O, S) Bonds

Silicon and its compounds with other heteroatoms have received considerable attention, particularly because of their applicative ability. Silicon forms a large number of compounds with other p‐block elements (e.g., C, N, S, O, F, Cl, and others). All of them affect practical chemistry to some extent and are characterized by unique properties. This article highlights recent developments and covers the literature from the last 10 years. It is mainly focused on catalytic methods for silicon–nitrogen, silicon–phosphorus, silicon–oxygen, and silicon–sulfur bond formation. The scope and applications of these practical compounds will also be discussed.

Chemoselective and Catalyst-Free O-Borylation of Silanols: A Facile Access to Borasiloxanes

This paper demonstrates the first highly chemoselective syntheses of various borasiloxanes from hydroboranes and silanols, achieved through catalyst-free dehydrogenative coupling at room temperature. This green protocol, which uses easily accessible reagents, allows for the obtaining of borasiloxanes under air atmosphere and solvent-free conditions.

Silylative coupling of olefins with vinylsilanes in the synthesis of functionalized alkenes

The development of highly selective methods for the synthesis of functionalized olefins, based on sequential catalytic reactions of organometallic reagents, has been the subject of extensive study because of their versatile applications in organic synthesis and materials science. The silylative coupling of olefins with vinyl-substituted organosilicon compounds (discovered in our group) represents one of the most efficient and straightforward methods for the synthesis of stereodefined alkenylsilanes and bis(silyl)alkenes, which are particularly attractive scaffolds for further transformations including palladium-catalyzed cross-coupling with organic halides (Hiyama coupling) or electrophile-induced desilylation. The article highlights the recent developments and covers the literature mainly from the last decade in the sequential (also one-pot) synthetic strategies including ruthenium-catalyzed silylative coupling followed by desilylative cross-coupling, acylation and halogenation, leading to stereodefined organic derivatives such as (E)-alkenyl halides, (E)-α,β-unsaturated ketones or arylene-(E)-vinylene derivatives which are widely applied as fine chemicals, functional materials or building blocks in organic synthesis.