(This is an excerpt from several messages between a
student and myself. I have removed the headers.)
From: AA
Date: October 21, 2007 1:27:09 PM EDT
Subject: TLOC - Purchase Inquiry (10/21/07)
21 October 2007
Could you sell a hard-copy of TLOC, ...
Certainly, just send a $35
money order to …
and I'll answer any questions you might have. What text are
you using?
Ege, 6th ed.
(http://college.hmco.com/chemistry/organic/ege/organic_chem/5e/instructors/)
Actually, the class had the option of using the book we
used for orgChem I or getting the newly adopted bruice, 5th
ed.
I am having some difficulty with reaction mechanisms or,
more specifically, combining multiple mechanisms to reach
final products. I'd like to think that the professor
is simply using more examples and/or test bank material
from the bruice book, as I am not faring as well as I would
like on his quizzes. I would just like more exposure
to the basic concepts involved in the mechanisms we are
studying this semester.
I had used
an early version of Ege, but we too switched to Bruice.
TLOC was roughly formed around Bruice...
If you are using Bruice in your class, I can tell you which
problems from TLOC will match the chapters. I don't know
that I can do that with Ege.
while I plan to master all mechanisms necessary to
understand the orgChem reactions we are studying, what I
currently need help with are chapters 16-18 in bruice, 5th
ed.
I have a quiz in orgChem II on wednesday.
Are you able to learn the
reactions or do you have questions? As you work on it. Make
absolutely certain that your curved arrows are 100%
correct. There cannot be any errors at that stage as it
contains the logic of a reaction. The problems are written
correctly. You just need to follow it.
I don't know how much you know, but past experience tells
me you are or may be learning the reactions for the first
time. You probably pattern matched to products before, and
now the problems are getting a lot more difficult and that
doesn't work. This seems simple to me, but if a chapter is
on additions to a carbonyl group, that is the very first
step in all of the reactions. I am always surprised when I
see some other reaction being written. That is one of the
things I liked about Bruice. For each chapter, you should
have some idea about the reactions.
The more you do, the easier it gets!
I am learning these
reactions for the first time. you're correct, in that
I have previously worked on (looked for) patterns.
**quick question: would a list of reagents going and
list corresponding "attacks"/"mini-reactions" be a futile
exercise? or would this lend itself to your methods?
I really don't know the answer to
that question. Early in my teaching career, I had planned
to prepare lists like that. Paula Bruice has such a list in
her book, but I can't say whether it is a valued
exercise.
If you were to ask which effort would bring a greater
likelihood of success, knowing whether a given reagent will
attack or to memorize reactants and products versus knowing
how a reaction takes place, I'd argue knowing how a
reaction takes place is more valuable. If you were to
substitute another reagent in place of the one you
memorized, I don't know if you would know what the product
would be because the problem has changed. If you know how
the reaction takes place, then you will have some
mechanistic expectation of the new reagent. If it must add
to a carbonyl group, does it have electrons that can be
donated? If the electrons are between a carbon and a metal,
you can use a generalization that the metal never holds the
electrons. If you noted my Chapter 1 discussion about
atoms, you would know that carbon does not hold its
electrons very closely. Therefore they are available for
reaction.
In class, I began to expect that students who
used flash cards would score lower than those
that just learned mechanisms. Flash cards may be fast and
easy, but they didn't follow my thinking of how our brains
learn the language of organic chemistry. Mechanisms contain
a chemical logic ...
What I don't know about your class is whether your
instructor waters down mechanisms and reactions. Does he
avoid either? Does he focus on nomenclature or ??? (fill in
topic)? Some instructors choose a book to avoid
mechanisms.
my prof has been laying out all the mechanisms, but very
quickly. he doesn't really go into the steps
involved. he just shows the mechanism, says "this is
such and such mechanism", then moves to the next.
there are plenty in the carbonyl-specific section.
Sometimes I used slides
from Part A, and added the curved arrows. I did that just
so I could discuss the reactions. Since students had the
reactions also, they could fill them in. That probably
wasn't as good as just walking around the class and asking
the students to fill them in. If students made common
errors, then I would make announcements or think about how
I needed to change my book.
I am amazed at how much I
can do already with the help of your work. just
yesterday morning, I couldn't predict products or suggest
reactants for reactions involving acyl halides, anhydrides
and esters. now, it seems sort of silly that I had
such a hard time with these at all. during breaks at
work and over lunch, I have just been writing them out ....
doing practice problems ... reviewing mistakes, which are
not as frequent now ... writing them out again ... practice
problems, etc.
I am moving into amides and nitriles tonight.
tomorrow, on to acid/base catalyzed hydrolysis ... this is
becoming fun ... almost like a puzzle. I can tell
where things must "fit" once I know what they are reacting
with or what they will become. I can see where trying
to memorize reactants wouldn't really serve my
understanding too well. I may forget a step/reactant
working this way.
Thank you for the
endorsement. Although I didn't always hear such comments,
but I heard them pretty frequently. I would not have
ventured into trying to market this book unless I had
students telling me this.
If you like the book, tell your friends and tell your
professor.
I just wanted to let you know ... I had an exam in
OrgChemII on Monday of this week. I got an 89% (class
avg was about 49%). I am sure the improved
performance I enjoyed was due primarily to your text AND
heeding your encouragement to actually write the mechanisms
out instead of trying to memorize the reactants, products,
etc. I had heard that this was necessary
before. This argument, coming from you, was
apparently what I needed to get in gear.
I am pleased to learn of
your good results. Students able to get 89% are the kind of
students I want to attract. So you went into the exam with
knowing how reactions take place and voila, you could
predict the product with that knowledge. This seems too
simple, doesn't it?
Tell your friends.
I hope this message finds
you well. I wanted to thank you again for TLOC.
I believe the practice I had in using your book really
helped with my overall understanding of organic chemistry
mechanisms.
My organic chemistry II final was last week. I got an
A in the class.
I am pleased to learn of
your results, and I am happy that you persevered. It
seems obvious to me that you should be able to solve at
least one example of a problem to solve another similar
problem, but it is difficult to get students to follow that
advice, especially in my absence. What you did is what
I did in college and your results are my results. For this
reason, I love getting good students to use my book, they
usually do really well. You simply validate what I saw in
my classes. I have less knowledge of how students do in
other classes, so I am pleased to learn of your
results.
Best,
PW
PS, thanks for giving me all of the great quotes,
see
www.curvedarrowpress.com for your others. This too will make it
there (eventually).