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Pericyclic Reactions: FMO Approach is a program
for Macintosh computers in which the frontier molecular
orbital approaches to electrocyclic and cycloaddition reactions
are animated. The bonding or antibonding interactions of
the frontier molecular orbital(s) determine whether the
reactions are thermally or photochemically allowed or forbidden.
Pericyclic reactions that involve a redistribution of
bonding and nonbonding electrons in a cyclic, concerted
manner are an important class of organic reactions. Since the
publications of the Woodward-Hoffmann rules on the
conservation of orbital symmetry (1) and the frontier molecular
orbital theory (FMO) by Fukui first described in the late
1960s (2), the underlying principles of these processes at the
molecular level have become fully understood. Many
modern organic chemistry textbooks include pericyclic reactions as
a major topic. They are usually covered in detail in a
typical introductory organic chemistry course.
In the Classroom
Between the two fundamental approaches to
pericyclic reactions, the FMO approach has gained some popularity
at the undergraduate teaching level. It is simpler and can
be based on a pictorial approach. A detailed understanding
of molecular orbital theories and symmetry is not required.
Screen from Pericyclic Reactions: FMO Approach
When learning the mechanisms of organic reactions,
our students have often expressed a wish that they could see
how the electrons "jump" and the orbitals "move" in the
microscopic world. Pericyclic Reactions: FMO Approach has
partially fulfilled the students' request. With its color 3-D
graphics and animation, Pericyclic Reactions: FMO Approach
can greatly enhance the teaching and learning of the FMO approach
to pericyclic reactions. The stereochemical
outcomes of these highly stereospecific reactions can be seen clearly
as the reaction process is animated on the computer
screen. Based on the previous protocols (3) on the Apple II
computer, we designed Pericyclic Reactions: FMO Approach
using Macromedia Director (4) to teach the two most
important pericyclic reactions: electrocyclic addition and
cycloaddition. Pericyclic Reactions: FMO Approach can be used
in intermediate or advanced organic chemistry courses.
Literature Cited
1. Woodward, R. B.; Hoffmann, R.
The Conservation of Orbital Symmetry; Academic: New York, 1971.
2. Fukui, K. Tetrahedron
Lett. 1965, 2009, 2427.
3. Lee, A. W. M. Educ.
Chem. 1988, 122.
4. Macromedia
Director, version 4.0.3; Macromedia, Inc.: San
Francisco, 1994.
Keywords
Lecture Aid; Computer Room; Organic; Pericyclic
Reactions; Molecular Orbitals
Hardware and Software Requirements
for Pericyclic Reactions: FMO Approach
Ordering and Information
Journal of Chemical Education
Software (often called JCE Software) is a publication of the
Journal of Chemical Education. There is an Order Form inserted in this issue that provides prices and other ordering information. If
this card is not available or if you need additional information, contact:
JCE Software, University of
Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1396; phone: 608/262-5153 or 800/991-5534; fax:
608/265-8094; email: jcesoft@chem.wisc.edu. Information about all our publications (including abstracts, descriptions, updates) is
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