University of Louisville
Synthesis of Gem-Difluoro Homopropargyl Alcohols via an Aqueous, Bimetallic (InZn) Barbier Reaction
Institution
University of Louisville
Faculty Advisor/ Mentor
Gerald B. Hammond; Satoru Arimitsu
Abstract
Indium is a useful metal for Barbier reactions in aqueous media, allowing for “green chemistry” C-C bond formation. This methodology has been applied to the reaction of α,α-difluoropropargyl bromide and several aldehydes to obtain gem-difluoro homopropargyl alcohols as the major product, in good yields, without the problem of α- defluorination. However, the drawback of this method is the cost of Indium; thus finding a cheap metal with similar effects is key to enhancing the accessibility of this methodology. Eight metals were selected by price and electron potential and screened alongside two additives. A system of In (0.1 eq.), Zn (0.9 eq.), and I2 (0.1 eq.) was found to be most cost effective, producing alcohols in moderate yields and lowering the yield of dimer byproduct. The utility of this method was explored using various aldehydes. Furthermore, to show the synthetic utility, the iodine promoted cyclization of an analogous propargyl alcohol was studied.
Synthesis of Gem-Difluoro Homopropargyl Alcohols via an Aqueous, Bimetallic (InZn) Barbier Reaction
Indium is a useful metal for Barbier reactions in aqueous media, allowing for “green chemistry” C-C bond formation. This methodology has been applied to the reaction of α,α-difluoropropargyl bromide and several aldehydes to obtain gem-difluoro homopropargyl alcohols as the major product, in good yields, without the problem of α- defluorination. However, the drawback of this method is the cost of Indium; thus finding a cheap metal with similar effects is key to enhancing the accessibility of this methodology. Eight metals were selected by price and electron potential and screened alongside two additives. A system of In (0.1 eq.), Zn (0.9 eq.), and I2 (0.1 eq.) was found to be most cost effective, producing alcohols in moderate yields and lowering the yield of dimer byproduct. The utility of this method was explored using various aldehydes. Furthermore, to show the synthetic utility, the iodine promoted cyclization of an analogous propargyl alcohol was studied.