The goal of asymmetric catalysis is to synthesize chiral compounds
out of achiral substrates. A chiral compound has a unique handedness;
it cannot be superimposed upon its mirror image, just as the right
hand cannot be superimposed on the left. Many biological molecules are
naturally chiral—amino acids and sugars, for instance—and the
demand for chiral compounds in the pharmaceutical, agricultural, and
chemical industries has been escalating rapidly. Most pharmaceutical
drugs, for instance, are now chiral compounds and are usually what are
known as single enantiomers, which are composed of only one of the two
mirror-image isomers. This month, Special Topics looks at the research
trends in asymmetric catalysis over the past decade as well as over
the past two years.
In the past decade, the hot research topics in asymmetric catalysis
cover a wide spectrum of techniques and catalysts for the synthesis of
chiral compounds. Among the many reactions discussed are the
asymmetric transition of metal-catalyzed allylic alkylations; the use
of chiral ruthernium complexes to affect asymmetric hydrogenation;
asymmetric catalysis with water, with optically-active manganese
complexes, with proline for catalyzing asymmetric aldol reactions, and
with nitrogen-containing ligands, platinum, palladium, and Schiff base
catalysts for facilitating asymmetric transfer reactions.
Over the past two years, the list of hot papers in asymmetric
catalysis includes those discussing the use of rhodium, praline, and
zinc complexes as catalysts. Another area that has generated a handful
of hot papers over this period is the direct catalytic asymmetric
Mannich-type reactions, which are used for the synthesis of chiral
nitrogen-containing compounds. Other research topics on the two-year
top 20 list include the use of asymmetric catalysis for the synthesis
of aziridines, the synthesis of modified BINOL ligands, and the
combination of enzyme and metal catalysts to achieve enantioselective
organic reactions.
Methodology
To construct this database,
papers were extracted based on title-supplied keywords for Asymmetric
Catalysis. The keywords used were as follows:
asymmetric AND
catal*
The baseline time span for this database
is 1995-2005 (fourth bimonthly). The resulting database contained 3,668 (10 years)
and 1,342 (2 years) papers; 6,297 authors; 52 countries; 189 journals; and
899 institutions.
Rankings
Once the database was in place,
it was used to generate the lists of top 20 papers (two- and ten-year
periods), authors, journals,
institutions, and nations, covering a time span of 1995-2005 (fourth
bimonthly, a 10-year + 8-month period).
The top 20 papers are ranked
according to total cites. Rankings for author, journal, institution,
and country are listed in three ways: according to total cites, total
papers, and total cites/paper. The paper thresholds and corresponding
percentages used to determine
scientist, institution, country, and journal rankings according to
total cites/paper, and total papers respectively are as follows:
| Entity: |
Scientists |
Institutions |
Countries |
Journals |
| Thresholds: |
16 |
19 |
11 |
3 |
| Percentage: |
1% |
5% |
50% |
50% |
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