Disulfidebonds are a significant motif in life and drug-delivery systems. In particular, steric hindrance and stereoscopic disulfidelinkers are closely associated with the stability of antibody–drug conjugates, which affects the potency, selectivity, and pharmacokinetics of drugs. However, limited availability and diversity of tertiary thiols impede the construction of steric and stereoscopic disulfides
N,N-bis(trimethylsilyl)methoxymethylamine as a convenient synthetic equivalent for +CH2NH2: primary aminomethylation of esters
作者:Kohji Okano、Toshiaki Morimoto、Minoru Sekiya
DOI:10.1039/c39840000883
日期:——
The introduction of a primary aminomethyl unit at the α-position of esters can be achieved in high yield by the silyltrifluoromethanesulphonate-catalysedreaction of ketenesilylacetals (2) with N,N-bis(trimethylsilyl)methoxymethylamine (1).
Enantioselective Thiourea-Catalyzed Additions to Oxocarbenium Ions
作者:Sarah E. Reisman、Abigail G. Doyle、Eric N. Jacobsen
DOI:10.1021/ja801514m
日期:2008.6.1
Asymmetric, catalytic reactions of oxocarbeniumions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbeniumion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities
It was found that the reaction of O-silylated enolates of carboxylicesters and of lactones with aminomethyl ethers proceeds smoothly under a catalytic action of zinc chloride to afford the corresponding α-aminomethylated carboxylicesters or lactones, except only one case using O-silylated enolate of δ-valerolactone, in which the resultant α-aminomethyl-δ-valerolactone is somewhat unstable and undergoes
Novel α-formylation of α,α-disubstituted esters. Trimethylsilyl trifluoromethanesulphonate-catalysed reaction of ketene silyl acetals with N-t-butylformimidoyl cyanide
作者:Kohji Okano、Toshiaki Morimoto、Minoru Sekiya
DOI:10.1039/c39850000119
日期:——
General α-formylation of α,α-disubstituted methyl acetates can be achieved by the reaction of ketenesilylacetals (1) with N-t-butylformimidoylcyanide (2) in the presence of trimethylsilyl trifluoromethanesulphonate (3) as catalyst followed by hydrolysis of the products (4) and/or (5) with copper(II) acetate or hydrogen chloride in aqueous methanol.