Indium(III)-Catalyzed Addition of Diethyl Acetamidomalonate to Terminal Alkynes:  An Efficient Approach to β-Branched α-Amino Acids

Abstract

The indium(III)-catalyzed Markovnikov addition of active methylene compounds to terminal alkynes has been expanded further to include diethyl acetamidomalonate. This reaction has been studied, and a practical approach to beta-branched alpha-amino acids was developed.

InI3‐ or ZnI2‐Catalyzed Reaction of Hydroxylated 1,5‐Allenynes with Thiols: A New Access to 3,5‐Disubstituted Toluene Derivatives

“…In addition to zinc halides, InBr 3 and InI 3 were also found to promote the reaction as catalysts ( Table 1, entries 14-16). [13,14] Finally, the optimized reaction condition was identified as follows: with 10 mol % of InI 3 , in 1,2-dichloroethane at 80 8C. Under such conditions, the reaction afforded the product 6 a in 73 % yield.…”

Recent Developments in Indium Metal and Its Salts in Organic Synthesis

“…[110] It has been reported recently that In(OTf) 3 -catalyzed additions of diethylacetamido malonates to terminal alkynes in the presence of N-methylmorpholine give an addition product which can easily be converted into β-branched α-amino acids in two steps with high enantiomeric purity [111] (Scheme 32).…”

Total Synthesis of (−)-Cinatrin C1 Based on an In(OTf)3-Catalyzed Conia-Ene Reaction

“…Recently, in connection with a project directed toward the synthesis of biologically intriguing natural products having a highly functionalized heterocyclic core such as lactacystin, salinosporamide A, and oxazolomycin, we have developed a new methodology for heterocycle synthesis that relies upon In(OTf) 3 -catalyzed Conia–ene reaction − of heteroatom-tethered acetylenic malonic ester 1 giving 2 (Scheme ). This method is applicable to chiral terminal and nonterminal alkynes giving various five- to seven-membered nitrogen- or oxygen-containing heterocyclic compounds stereoselectively without significant amounts of racemization.…”