Week-1-Lecture-slides - Welcome to Chemistry 51B Prof...

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Unformatted text preview: Welcome to Chemistry 51B Prof. Gregory A. Weiss University of California, Irvine 1 Assigned Reading: pp. 314-344, 346-350 Assigned Problems: 9.1, 9.6-9.8, 9.12-14, 9.16, 9.19, 9.21-22, 9.26, 9.29, 9.31, 9.37, 9.48, 9.50, 9.58-59, 9.66, 9.70-71, 9.75 Monday, March 31 Introduction Course organization How to succeed in organic chemistry Ch. 9 = 3 lectures (alcohols, ethers & epoxides) Intro to functionalities How to synthesize 2 Instructor: Prof. Gregory Weiss Office: 4122 NS-1 Email: [email protected] (follow instructions) TAs: Lucie Lee and Ben Kohn Email: [email protected] and [email protected] Chemistry 51B Organic Chemistry 3 Chemistry Dept. = Free! http://www.chem.uci.edu/undergrad/tutors Kevin Pham Tue 11am - 1pm Wed 12am - 2pm Thur 2pm - 4pm LARC: http://www.larc.uci.edu/ 4 Chemistry & LARC: Free Tutoring This week's office hours Prof. Weiss: Today 11-noon (4122 NS-1) Thursday office hour cancelled this week Lucie Lee: Friday, 2-3, outside 4126 NS-1 Ben Kohn: Tuesday, 10-11, outside 4126 NS-1 5 If not, send an email to me at [email protected] Did you receive an email from me? Must come from an @uci.edu address 6 How to send Prof. Weiss an email Must come from @uci.edu address. Include descriptive subject line Begin with correct salutation ("Prof. Weiss,") Be concise Use email sparingly End with your full name and ID number 7 Discussion Sections Start next week Go to any discussion section Weekly worksheet posted on-line Important for success in organic chemistry Day M M M Tu Tu Th F F Time 11:00-11: 5 0 1:00-1:50pm 3:00-3: 5 0 p 11:00-11: 5 0 1:00-1:50pm 12:00-12:50p 10:00-10: 5 0 1:00-1:50pm Building HICF RH SSPA MSTB SSPA ICF SS L SSPA Room 100P 188 1170 114 1170 101 145 1170 Instructor LL LL LL BK BK LL BK BK 8 How will you determine my grade? Midterm I, Monday, April 21st 25% Midterm II, Monday, May 19th 25% Final Exam, June 11th 45% Participation <2% Possible quizzes: 5% Based upon previous years' grades... Median grade: C+ 20% receive A/A30% receive B-/B/B+ www.pickaprof.com 9 Can earn 8 points out of 400 (2%) Strongly recommended Attend informational session Bren Hall 4011 Wed, Apr 2, 11am Wed, Apr 2, 2pm Thu, Apr 3, 10am Thu, Apr 3, 2pm Deadlines: Midnight, April 20: 10 random problems + assigned problems #1-3 Midnight, May 18: 10 random problems + assigned problems #4-6 Midnight, June 10: 10 random problems + assigned problems #7-10 Note: Synthesis problems generated must have "max steps" set to at least 2 to count for credit. Extra credit: Online reaction tutorial Problems or Questions: Help notes and pages are available on the system website, otherwise contact Jonathan Chen: [email protected] 10 Caution!! Read syllabus carefully. Note academic honesty & dishonesty policy. No makeup exams. No extra time given. Need to show up on time. Show up early. Seating will be assigned. IDs will be checked. 11 Add / Drop The Prof and TAs do NOT sign add/drop cards. First, two weeks = WebReg for changes No changes (add/drop/grade) after April 11th 12 The assigned problems From both HW and online reaction tutorial Highly recommended - for obvious reasons 13 On another note Avoid asking Prof. Weiss, "do we have to know this for the exam?" He reflexively says "yes" everytime. Every single time. Ask yourself first: Covered in lecture? Covered on HW? If yes, then... and in HW problems Pay attention to what's emphasized in class 14 How to succeed in Organic Chemistry Impress your friends! It's fun! It's easy! Just follow these steps! Read ahead. Attend every class. Take notes. Attend a discussion section Do the assigned problems. Every single one. No cheating. Do the unassigned problems. Study independently first and, then, in groups. 15 A few words of wisdom Cramming is the road to failure. Pay attention to chemical trends. O-chem cannot be mastered by pure memorization. Fall behind .... And certain doom awaits.... Learn by repetition. Repetition. Repetition. 16 Memorization tips Make lists of reagents and molecules, emphasizing trends Make flashcards with reactions / reagents Study right before going to sleep, and right after waking up Study a set amount per day recommended: 1-2 hrs 17 The course website https://eee.uci.edu/08s/40528 Postings include Slides Practice problems and worksheets Seating assignments Nothing else Need to attend lectures and take notes 18 R==any functional grp (often alkyl) X El any functional grp E, = electrophile Nu, Nuc = nucleophile Rxn = reaction Me = methyl XS = excess Et = ethyl Pr = propyl (i-Pr) RDS = rate determining Bu = butyl (i-Bu, t-Bu) step Ph = phenyl e- = electron Ar = aryl (aromatic ring) Ts = tosylate, Tf = triflate, Ms = mesylate Key abbreviations 19 New functionalities Recall oxygen = electronegative, 2 lone pairs (lp's) Alcohols (ROH) O Ethers R R Epoxides O R 20 ROH Nomenclature OH functionality H-bonding donor & acceptor Alcohols 21 Those trends I warned you about... How close can the molecules get to each other? H-bonding dominates alcohol trends 22 Famous alcohols Ethyl alcohol 4000+ yrs of human synthesis Starch and cellulose 23 Ethers Vapor = Denser than air Nomenclature Properties and reactivity = Mostly none Inert & Boring 24 Famous ethers Anesthesia = diethyl ether ("the bat") Crown ethers 25 Epoxides Nomenclature = complicated & unimportant Reactivity = impressive 26 Famous epoxides Often found in reactive bioactive compounds 27 How to make alcohols and ethers Nucleophilic substitution 28 OH = Bad LG Useful intermediates and starting materials Inert enough to use as race car fuel Reactions of alcohols 29 Elimination of alcohols Requires strong acid Beta elimination (carbon next to OH carbon) Yields alkene AKA dehydration 30 Dehydration of Primary Alcohols E2 rather than E1 elimination Due to instability of 1 carbocation 31 Zaitsev's rule Follows stability trends More substituted alkene = preferred product A.M. Zaitsev (1841-1910) 32 Le Chatelier's Principle Redux Drive reactions by adding XS starting materials Drive reactions by removing product(s) Henri Louis le Chtelier (1850-1936) 33 Common for any carbocation intermediate forming reaction (e.g., SN1 and E1) Carbocation Rearrangments The drive towards stability 34 Dehydration reagents POCl + pyridine Nature's strategy is similar... 3 35 Useful reaction, as OH is not a viable LG Converting the OH to halide 36 Better ways to convert OH into Halide SOCl substitutes Cl PBr substitutes Br See mechanism in book (similar to POCl ) 2 3 2 37 Tosylate = super LG Mesylate = Variant = super duper LG Even better LG's from OH 38 Good reaction sequence for doing useful things with OH group Convert to LG, then substitute Note: net inversion of configuration 39 Reactions of Epoxides Versatile and useful intermediate Extensively used in the preparation of polymers (e.g., epoxy flooring) and pharmaceuticals 40 Strong nucleophiles open with backside attack, suggestive of SN2 reaction substitution at the more substituted carbons suggest SN1 contribution. N2 The stereo- and regio-chemistry of epoxide ring opening reactions However, preference for Reality = in between S SN1! and 41 ...
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This note was uploaded on 04/26/2008 for the course CHEM 51B taught by Professor Taagapera during the Winter '08 term at UC Irvine.

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