Catalytic stereoselective addition to alkynes. Borylation or silylation promoted by magnesia-supported iron oxide and cis-diboronation or silaboration by supported platinum nanoparticles

Abstract

Asiri, AM.; Kosa, SA.; García Gómez, H.; Grirrane, A. (2015). Catalytic stereoselective addition to alkynes. Borylation or silylation promoted by magnesia-supported iron oxide and cis-diboronation or silaboration by supported platinum nanoparticles. Journal of Catalysis. 329:401-412. doi:10.1016Catalysis. 329:401-412. doi:10. /j.jcat.2015. Catalytic Activity of Cationic and Neutral Silver(I) XPhos Complexes with N ligands or Tolylsulfonate for Mannich and Aza-Diels-Alder CouplingsAbdessamad Grirrane,* [a] Eleuterio Álvarez, [b] Hermenegildo García,* [a] and Avelino Corma* [a] Abstract: Cationic and neutral silver(I)-L complexes (L = Buchwaldtype biaryl phosphanes) with N co-ligands and organosulfonate counterion have been synthesized and characterized by structural and spectroscopic properties. At room temperature, both cationic and neutral silver(I)-L complexes are extremely active catalysts to promote the single and double A 3 -coupling of terminal (di) alkynes, pyrrolidine and formaldehyde. Also the aza-Diels-Alder two and three -coupling of Danishefsky's diene with imine or with amine and aldehyde can be efficiently catalysed by these cationic or neutral silver(I)-L complexes. The solvent can influence the catalytic activity performance due to limited complex solubility or to solvent decomposition and reactivity. Isolation of new silver(I)-L complexes with reagents as ligands lend support to mechanistic proposals for such catalytic processes. The activity, stability and metal-distal arene interaction of these silver(I)-L catalysts have been compared with that of analogous cationic gold(I) and copper(I) complexes.

Activation of the Si–B interelement bond related to catalysis

“…Later, a platinum-catalysed method in the presence of supported platinum nanoparticles was reported by Grirrane and co-workers (34a -E-39a, Scheme 8, bottom). 23 As in Stratakis's work, no additives or ligands were needed.…”

“…In 2015, Grirrane and coworkers introduced a highly regio-and stereoselective silylation of phenylacetylene using Me 2 PhSi-Bpin (18) as the silicon source and Fe/MgO nanoparticles as catalyst (34a -E-53a, Scheme 16). 23 A blank experiment showed that FeO is crucial to the high yield.…”

Copper‐Catalyzed Triboration of Terminal Alkynes Using B2pin2: Efficient Synthesis of 1,1,2‐Triborylalkenes

“…[2a, 15] The first metalcatalyzed diboration of alkynes was reported by Suzuki and Miyaura in 1993 using a Pt catalyst, [16] and significantly improved Pt catalyst systems were reported by our group. [17] During the last few years, Pd, [18] Cu, [19] Co, [11c, 20] Fe, [21] Zn, [14x] and metal-free [22] systems were reported for the diboration of alkynes, which provide practical and economic alternatives to the Pt-catalyzed processes (Scheme 2 b). [16][17]23] However, the availability of diverse multiborylalkenes is quite limited because of the lack of efficient and versatile synthetic methods.…”

Alkenyl-Functionalized Open-Cage Silsesquioxanes (RSiMe2O)3R′7Si7O9: A Novel Class of Building Nanoblocks

“…The leading representatives of trifunctional IC-POSS s are commercially available trisilanols (HO) 3 R′ 7 Si 7 O 9 (R′ = Et, i -C 4 H 7 , CH 2 CH(CH 3 )CH 2 C(CH 3 ) 3 or Ph, trisilanol-POSS). 14 They have been prepared by hydrolytic condensation of RSiX 3 (X = Cl, OR, etc.) 15 − 17 or by the controlled cleavage of R 8 Si 8 O 12 .…”