Preparation of Polyfunctional Zinc Organometallics Using an Fe- or Co-Catalyzed Cl/Zn-Exchange

Abstract

A new Fe- or Co-catalyzed Cl/Zn-exchange reaction allows the direct transformation of aryl, heteroaryl, and also alkyl chlorides into the corresponding zinc reagents. The method tolerates functional groups such as a nitrile or an ester. Remarkably, secondary and tertiary alkyl chlorides are suitable substrates for the Cl/Zn exchange.

A New Method for the Preparation of Non‐Terminal Alkynes: Application to the Total Syntheses of Tulearin A and C

“…In fact, addition of Cu(acac) 2 (10 mol %) to a mixture of 4 and MeLi in Et 2 O led to a significant rate acceleration without compromising the yield or purity of the resulting product (entry 4). Even faster is the reaction in the presence of Fe(acac) 3 (5-10 mol %), although it was mandatory to use 1,2-diaminobenzene as an additive (entry 5); [30][31][32] in its absence, the reaction was unselective and product isolation therefore troublesome.…”

Recent Advances of the Halogen–Zinc Exchange Reaction

“…Adamantyl chloride ( 127 ), for example, is treated with the zincate 128 in the presence of Fe(acac) 2 (10 mol %) and 4‐fluorostyrene (20 mol %). After quenching of the resulting metal species with MeSO 2 SMe, the thioether 129 is obtained in 66 % yield (Scheme ) . To expand the scope of this exchange reaction, the zincate 130 was developed.…”

“…Thus, trichlorinated arene 131 is treated with 130 in the presence of Co(acac) 2 (20 mol %) and 4‐fluorostyrene (50 mol %) at elevated temperatures (50 °C, 5 h). Quenching of the resulting organometallic with PhSO 2 SPh produces the diarylthioether 132 in 63 % yield (Scheme ) …”

“…30d Af urthere xtension is achieved, when electron-rich triorganozincates are combinedw ith iron or cobalt catalysts, which enables chlorine-zinc exchange reactions. [31] Adamantyl chloride (127), for example, is treated with the zincate 128 in the presence of Fe(acac) 2 (10 mol %) and4 -fluorostyrene (20 mol %). After quenching of the resultingm etal species with Scheme17.…”

“…MeSO 2 SMe, the thioether 129 is obtained in 66 %y ield (Scheme 22). [31] To expand the scope of this exchange reaction, the zincate 130 was developed. However,t he catalytic system needs to be modified and Co(acac) 2 provides best results.…”