Carbozincation of Substituted 2-Alkynylamines, 1-Alkynylphosphines, 1-Alkynylphosphine Sulfides with Et2Zn in the Presence of Catalytic System of Ti(O-iPr)4 and EtMgBr

Abstract

The EtMgBr and Ti(O-iPr)4-catalyzed ethylzincation of 1-alkynylphosphine sulfides with Et2Zn in diethyl ether followed by hydrolysis and deuterolysis affords corresponding β,β-disubstituted 1-alkenylphosphine sulfides with high yield. The EtMgBr and Ti(O-iPr)4-catalyzed reaction of 2-alkynylamines, 1-alkynylphosphines, and 1-alkenylphosphine sulfides with Et2Zn in various solvents was studied. It has been found that the reaction of 2-alkynylamines and 1-alkynylphosphines in methylene chloride, hexane, toluene, benzene, and anisole leads to the selective formation of 2-alkenylamines and 1-alkenylphosphine oxides after oxidation with H2O2.

Synthesis of heteroatom-containing pyrrolidine derivatives based on Ti(O-iPr)4 and EtMgBr-catalyzed carbocyclization of allylpropargyl amines with Et2Zn

“…Further, the reaction goes well in Et 2 O, CH 2 Cl 2 , hexane, toluene, benzene and anisole but does not proceed in 1,4dioxane, tetrahydrofuran, 1,2-dichloroethane, 1,2-dimethoxyethane, chloroform, and triethylamine. 29 We studied carbocyclization of nitrogen-containing enynes in various solvents. At the same time, it must be taken into account that hexane (Et 2 Zn (1 M in hexane) and Ti(O-iPr) 4 (0.5 M in hexane)), and Et 2 O (EtMgBr (2.5 M in Et 2 O)) are always present in the reaction mixture.…”

“…Quite recently, we reported that Ti-Mg-catalyzed 2-zincoethylzincation of substituted 2-alkynylamines with Et 2 Zn proceeds equally selectively in diethyl ether, anisole, dichloromethane, hexane, benzene, and toluene. 29 In this study, we found that the formation of carbocyclization product 4f upon the reaction of N-(thiophen-2-ylmethyl)-N- We also succeeded to perform the carbocyclization of N 1 ,N 10diallyl-N 1 ,N 10 -bis(4-methylbenzyl)deca-2,8-diyne-1,10-diamine 8, prepared from 1,7-octadiyne, to give bis-methylenepyrrolidine derivative 9 (1,6-bis(4-methyl-1-(4-methylbenzyl)pyrrolidin-3ylidene)hexane) (Scheme 5).…”

“…It is worth noting that, unlike N,N-dialkyl substituted 2-alkynylamines, substituted acetylenic alcohols and their ethers are unreactive towards Ti-Mg-catalyzed 2-zincoethylzincation. 28,29 According to the reaction scheme that we proposed (Scheme 7), ligand exchange between Ti(O-iPr) 4…”

“…28 Now we demonstrate that the reaction of N,N-dialkyl-substituted 2-alkynylamines with Et 2 Zn catalyzed by the Ti(i-OPr) 4 -EtMgBr system results in the selective formation of 2-zincoethylzincation products. 28,29 Relying on analysis of the above literature, we assumed that Ti-Mg-catalyzed carbozincation of functionalized allyl-substituted propargylamines could serve for the development of selective one-pot methods for the synthesis of various methylenepyrrolidine derivatives. As a continuation of research on the Ti-Mg-catalyzed carbozincation of functionally substituted alkyne substrates, we studied here carbocyclization of a variety of allyl-substituted propargylamines.…”

Niobium- and zirconium-catalyzed reactions of substituted 2 alkynylamines with Et2Zn

“…Currently, we have demonstrated that 2zincoethylzincation of nitrogen-and phosphorus-containing acetylene derivatives with Et 2 Zn is accompanied by generation of low-valent titanium diisopropoxide complex. [52][53][54] Meanwhile, it follows from analysis of the literature that reduction of vecoordinate niobium compounds in the presence of acetylene substrates is accompanied by the formation of metal alkyne complexes. We were interested in studying the behavior of NbC1 5 in the Ti-Mg-catalyzed reaction of functionally substituted alkynes with Et 2 Zn, which we currently study.…”