A method for producing a reaction product comprising an ester-functional silane, the method comprising: i) reacting a composition comprising: a) a haloorganosilane, selected from chloromethyldimethylmethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-chloropropyldimethylmethoxysilane, 3-chloropropyldimethylethoxysilane, 3-chloropropylethyldimethoxysilane, 3-chloropropylethyldiethoxysilane, 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-iodopropyltrimethoxysilane, 3-iodopropyltriethoxysilane, chlorobutylphenylmethyl-n-propoxysilane, chloromethyldimethylmethoxysilane, or chloromethyltrimethoxysilane; b) a metal salt of a carboxy-functional compound, where the metal salt of a carboxy-functional compound has the formula [R 2 COO -] c [M c+], wherein R 2 is a substituted hydrocarbyl group, or unsubstituted hydrocarbyl having from 1 to 20 carbon atoms,or wherein R 2 is a substitute group selected from F, [-COO -] c [M c+], OH, OR 1, OCH 2 CH 2 OR 1, COOR 1, C(=O)NR 1 2, C(=O)NH 2, each M c+ is an alkali metal cation, alkaline earth metal cation, or ammonium cation and c is 1 or 2, and each R 1 is independently a hydrocarbyl group having from 1 to 10 carbon atoms, alternatively from 1 to 4 carbon atoms, c) a phase transfer catalyst comprising a polyazabicycloalkene, an N 2 -alkyl-polyazapolycyclo-alkenium compound, or a mixture thereof,, and d) a co-catalyst, where the co-catalyst comprises a compound of formula: M c+ R 14, where M c+ is alkali metal cation or alkaline earth metal cation; c is 1 or 2; and R 14 is a counter ion selected from the group consisting of Cl -, HSO 4 -, HCO 3 -, acetate, SO 4 2-, CO 3 2-, PO 4 3- and HPO 4 2- and provided that the co-catalyst is optional when the phase transfer catalyst comprises the N 2 -alkyl-polyazapolycyclo-alkenium compound. a) a haloorganosilane, selected from chloromethyldimethylmethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-chloropropyldimethylmethoxysilane, 3-chloropropyldimethylethoxysilane, 3-chloropropylethyldimethoxysilane, 3-chloropropylethyldiethoxysilane, 3-bromopropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-iodopropyltrimethoxysilane, 3-iodopropyltriethoxysilane, chlorobutylphenylmethyl-n-propoxysilane, chloromethyldimethylmethoxysilane, or chloromethyltrimethoxysilane; b) a metal salt of a carboxy-functional compound, where the metal salt of a carboxy-functional compound has the formula [R 2 COO -] c [M c+], wherein R 2 is a substituted hydrocarbyl group, or unsubstituted hydrocarbyl having from 1 to 20 carbon atoms,or wherein R 2 is a substitute group selected from F, [-COO -] c [M c+], OH, OR 1, OCH 2 CH 2 OR 1, COOR 1, C(=O)NR 1 2, C(=O)NH 2, each M c+ is an alkali metal cation, alkaline earth metal cation, or ammonium cation and c is 1 or 2, and each R 1 is independently a hydrocarbyl group having from 1 to 10 carbon atoms, alternatively from 1 to 4 carbon atoms, c) a phase transfer catalyst comprising a polyazabicycloalkene, an N 2 -alkyl-polyazapolycyclo-alkenium compound, or a mixture thereof,, and d) a co-catalyst, where the co-catalyst comprises a compound of formula: M c+ R 14, where M c+ is alkali metal cation or alkaline earth metal cation; c is 1 or 2; and R 14 is a counter ion selected from the group consisting of Cl -, HSO 4 -, HCO 3 -, acetate, SO 4 2-, CO 3 2-, PO 4 3- and HPO 4 2- and provided that the co-catalyst is optional when the phase transfer catalyst comprises the N 2 -alkyl-polyazapolycyclo-alkenium compound.