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Systematic Studies using 2‐(1‐Adamantylethynyl)pyrimidine‐5‐carbaldehyde as a Starting Material in Soai’s Asymmetric Autocatalysis
Author(s) -
Busch Mark,
Schlageter Martin,
Weingand Daniel,
Gehring Timo
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200900634
Subject(s) - autocatalysis , pyrimidine , chemistry , stereochemistry , organic chemistry , catalysis
Herein, we present a new substrate for the Soai reaction, which has an adamantylethynyl residue ( 1 g ) and exhibits asymmetric autocatalysis, yielding products with enantiomeric excesses above 99 %. For the first time, all reactions were performed on a parallel synthesizer system to ensure identical reaction conditions. A detailed systematic study of reaction parameters was performed and we report the highest enhancements of enantiomeric excess reported so far in the Soai reaction in one reaction cycle (7.2→94.1 % ee or 3.1→92.1 % ee ). Our results led to a set of reaction parameters that yield reproducible results. Therefore, our new starting material 1 g is suitable for systematic and mechanistic studies on this remarkable reaction. A series of experiments designed to quantify the amplification of enantiomeric excess demonstrated that the reaction can be used in principle as a tool for the detection of low enantiomeric excesses: under definite conditions, an unknown low enantiomeric excess (0.1–7 %) was amplified to a detectable one. A back calculation to the original value offers a new method for the determination of small enantiomeric excesses.