Chem 201 Archive – Alan Shusterman

Month: November 2009

  • Notes on epoxides and other Chapter 11 stuff

    A few reflections on the material from Monday morning’s lecture.

    Epoxide ring-opening. First, epoxides can react with strong nucleophiles without adding acid. The strained ring makes the epoxide reactive. These reactions look like SN2 reactions.

    Second, epoxides can react with much weaker nucleophiles by adding acid. Examples of weak nucleophiles include water, alcohols, carboxylic acids. The mechanisms of these reactions are a little strange. If one epoxide carbon is tertiary, the nucleophile adds there, but regardless of where the nucleophile adds, a backside attack occurs. So a little SN1 and a little SN2-like behavior all at the same time.
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  • Printing Acetylferrocene NMR – 2009

    Instructions for completing the acetylferrocene lab were posted online in 2008 and they still look relevant to me, so let’s try them again. The 2008 NMR printing instructions are posted here. I do not have a due date yet for the acetylferrocene lab, but it won’t be due *this week*.

  • Exam #3 results

    I posted answer keys for Homework #7 and for Exam #3 over
    the weekend. I have also finished grading Exam #3 and I tried to hand back as
    many exams as I could during class today. If you didn't receive your exam, stop by
    Kathy Kennedy's office (Rm. 303) to pick it up. I am still reading homework assignments (and
    lab reports) so more paper will come your way on Wednesday. (more…)

  • Lecture slides – Mon Nov 23

    Slides from today’s lecture can be viewed here.

    I didn’t quite get through everything that I had promised and I’m not taking a straight path through the chapter. If you would like to know what is coming next, here’s a list of the topics in the sequence that I will be talking about them:

    • preparation of epoxides using peroxycarboxylic acids (11.5 cont’d)
    • synthetic planning (10.9 and 11.9)
    • preparation of aymmetric epoxides (11.10 – updated Tues Nov 24)
    • reactions of ethers (11.3)
    • reactions of epoxides (11.4) ??

    ?? = depends on time constraints

  • Lab schedule Th & next week

    Lab continues to meet this week as normally scheduled.

    Lab lecture on Thursday night, Nov 19, is cancelled.

    The only lab operations scheduled for the following week, M-W, Nov 23-25, are wrapping up the acetylferrocene experiment. If students are unable to finish this experiment this week, they can perform any and all operations — run the reaction, separate the compounds on a column, analyze the results by TLC, measure melting points, or make NMR samples for us — they can do that next week during the scheduled lab periods.

    Special request – my lab assistants will be in the lab starting at 1:10 PM. I will let them leave the lab, however, if no students show up by 1:30 PM. So please come on time. If you need to make up lab work, but can’t get to the lab until after 1:30, please send me an email now so that I can pass this info along to my lab assistants. Thanks

  • Q&A session for Exam #3

    I will answer your questions on the material in chapters 1-9 on Tuesday, 6-7 PM, in Eliot 314.

    By the way, I will be running for the door immediately afterwards to make it to an off-campus appointment at 7:30 so please don’t wait until afterwards to ask special questions.

  • Final exam '09 date/time set

    I just noticed that the Registrar’s Office has posted dates and times for final exams. The final exam in this class will start at 6 PM on Tuesday, Dec 15 in the Psych auditorium and adjoining rooms. You can download the complete final exam schedule here.

  • What does SN2 transition state look like?

    The images and data table for the three SN2 transition states shown in lecture today can be viewed here.

  • Schedule changes: Exam #3, HW #6, Syllabus

    Since no strong objections were raised to the schedule changes that I had proposed, I have made the following changes for the upcoming exam, homework and classes (all of the appropriate online schedules have been updated to reflect these chanes):

    Exam #3 – Thursday, Nov 19, in conference. Please attend conference at your normal time and location. Bring a model kit. Keep in mind that some students may have already taken the exam or will be taking the exam later than you, so please do not blurt out anything about the exam and do not discuss the exam publicly until 2 PM.

    HW #6 – out late Monday, Nov 9; due Monday, Nov 16, noon; returned Wednesday, Nov 18, 9 AM.

    Syllabus – I am gaining an extra lecture day on Monday, Nov 16 and this will affect the lecture schedule for the rest of the term. I will start lecturing on Chapter 10 on Monday, Nov 16. There will be two additional lectures on Chapter 10 on Wednesday, Nov 18 (note that these first two lectures are coming before exam #3) and on Friday, Nov 20. There will also be a lab lecture on Thursday, Nov 19.

  • SN2 kinetics and geometry

    First, if you would like to see the MO pictures that I used in class today, check out last year’s post on back side attack & HOMO-LUMO overlap (Oct 13, 2008).

    There are also a couple of points that I want to add concerning reaction rates (kinetics):
    (more…)