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Chapter 15. Organometallic Compounds (R-M). Organomagnesium & Organolithium compds 15.1. Lithium Diorganocopper (Gilman) Reagents 15.2. No t covered: Organopalladium reagents, Heck reaction, carbenes, carbenoids, & alkene metathesis. Synthesis, Concepts and the Final. Recall pKa of alkanes.
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Chapter 15 OrganometallicCompounds(R-M) Organomagnesium & Organolithium compds 15.1 Lithium Diorganocopper (Gilman) Reagents 15.2 Not covered: Organopalladium reagents, Heck reaction, carbenes, carbenoids, & alkene metathesis. Synthesis, Concepts and the Final
Recall pKa of alkanes Organometallic Compounds R-Mg-X or R-M
covalent and ionic view Prep of Organometallic Compounds Grignard (organomagnesium compound) free radical like
Alkyllithium OR Prep of Organometallic Compounds Grignard
Prep of R-M (Nu:- +M) alkyl halide (sp3) + metal But also: vinyl halide (sp2) + metal aryl halide (sp2) + metal e.g. Grignard or organomagnesium reagent
Nucleophilic Reactions Attacks less hindered side of epoxide
Reactions Primary site inverted, secondary unchanged.
(similar Grignard reagent can be made) Lithium Diorganocopper Reagents Prep and use in Synthesis
Grignards and alkyllithiums can be nucleophiles….. Use: Substitution rxn, replace halides butcuprates are better
add eliminate* add eliminate* Use: Substitution, replace leaving group TMS = trimethylsilyl *not really SN2, ignore mechanism, 2nd semester
Better Organometallic Compounds Nucleophile attacks less hindered side of epoxide earlier = RMgX or RLi
SYNTHESIS Propose how to convert starting material (sm) to a target rules: Use any number of steps For each step show: - necessary reagents - necessary conditions - expected product or products SM target
SYNTHESIS Compare functional groups and carbon skeleton starting material target Need: 1 carbon (CN) and ketone + nitrile from olefin
NC-/DMF PCC Br2 H2Oxs SYNTHESIS retroanalysis SM target
RCO3H PCC NC-/DMF PCC DMSO H2O SYNTHESIS retroanalysis Br2 H2Oxs SM target
“thoughts” --- join--- synthesis How?
reverse? synthesis synthesis How? How? plan
DMF NBS hv target SM +
PBr3 Mg/THF RCO3H H+/H2O
compare carbon skeleton functional groups convert 2-bromopropene to 2-hexanone
compare carbon skeleton functional groups
dibromide source? How?
dibromide source? others?
dibromide source? others?
Final 200 pts: ~130 cumulative,~70 new material 5:30 pm PSC 002, (possibly 006) chapters 1-11, 15-15.2 3 hour exam, models, pencil NO calculators or cell phones Grades submitted (VIP), scores posted ASAP. Grade - determined by either: (1) accumulated total points (tests + final + recitation pts) or (2) final exam grade WHICHEVER IS HIGHER! I’ve enjoyed teaching the class! I appreciate your hard work.