Nomenclature Common: named as if derived from hydrogen halide, HX - PowerPoint PPT Presentation

Nomenclature Common: named as if derived from hydrogen halide, H–X

Nomenclature Common: named as if derived from hydrogen halide, H–X CH 3 –Cl methyl chloride

Nomenclature Common: named as if derived from hydrogen halide, H–X CH 3 –Cl methyl chloride (CH 3 ) 2 CH–Br isopropyl bromide Br

Nomenclature Common: named as if derived from hydrogen halide, H–X CH 3 –Cl methyl chloride (CH 3 ) 2 CH–Br isopropyl bromide Br R–X alkyl halide

Nomenclature Common: named as if derived from hydrogen halide, H–X CH 3 –Cl methyl chloride (CH 3 ) 2 CH–Br isopropyl bromide Br R–X alkyl halide grouped into 1 � , 2 � , 3 � classes based on identity of R

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane F

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F F

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F ( S )-3-fluoroheptane F

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F ( S )-3-fluoroheptane F Cl Br Br

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F ( S )-3-fluoroheptane F Cl ( Z )-5,5-dibromo-2-chloro-2-hexene Br Br

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F ( S )-3-fluoroheptane F Cl ( Z )-5,5-dibromo-2-chloro-2-hexene Br Br Br

Nomenclature IUPAC: named as substituted alkanes substituent name for X is halo R–X haloalkane 3-fluoroheptane F ( S )-3-fluoroheptane F Cl ( Z )-5,5-dibromo-2-chloro-2-hexene Br Br (1 R ,3 S )-1-bromo-3-methylcyclohexane Br

Some essential properties of haloalkanes • R–X are polar H δ− δ + C X H H

Some essential properties of haloalkanes • R–X are polar H δ− δ + C X H H the C of C–X is intrinsically electrophilic . This dominates the chemistry of this functional group •

Some essential properties of haloalkanes • R–X are polar H δ− δ + C X H H the C of C–X is intrinsically electrophilic . This dominates the chemistry of this functional group • • R–X have bp’s higher than corresponding R–H Cl bp - 0.5 � C bp 79 � C

Some essential properties of haloalkanes • R–X are polar H δ− δ + C X H H the C of C–X is intrinsically electrophilic . This dominates the chemistry of this functional group • • R–X have bp’s higher than corresponding R–H Cl bp - 0.5 � C bp 79 � C • R–X are toxic

Some essential properties of haloalkanes • R–X are polar H δ− δ + C X H H the C of C–X is intrinsically electrophilic . This dominates the chemistry of this functional group • • R–X have bp’s higher than corresponding R–H Cl bp - 0.5 � C bp 79 � C • R–X are toxic • R–X are relatively rare as natural products

Synthetic and Naturally Occurring Haloalkanes Cl Cl Cl Cl H O OCH 3 Cl Cl Cl Cl CH 3 DDT (insecticide) methyl ether of a trichloroorcinol LD 50 = 115 mg/kg (fungicide produced by water lillies) O - O Cl OSO 3 Cl OH Cl OH OH Cl OH Cl Cl Cl OH Cl Cl Cl Cl cytotoxic sulfolipid from Mytilus galloprovincialis IC 50 = 13 � M

Synthetic and Naturally Occurring Haloalkanes Cl Cl Cl Cl H O OCH 3 Cl Cl Cl Cl CH 3 DDT (insecticide) methyl ether of a trichloroorcinol LD 50 = 115 mg/kg (fungicide produced by water lillies) (compare LD 50 acetaminophen = 338 mg/kg) O - O Cl OSO 3 Cl OH Cl OH OH Cl OH Cl Cl Cl OH Cl Cl Cl Cl cytotoxic sulfolipid from Mytilus galloprovincialis IC 50 = 13 � M

OH Cl Cl O H O OH O HO O OH Cl sucralose (Splenda™) 400-800 times as sweet as sugar OH OH O OH H O H O O HO O OH OH sucrose

Hey! How about a bit of review: How many chiral centers does Splenda have? OH Cl Cl O H O OH O HO O OH Cl

How many chiral centers does Splenda have? OH Cl Cl O * H O * OH * * O HO * * O * * * OH Cl

How many chiral centers does Splenda have? nine What is the theoretical maximum number of stereoisomers can this sugar substitute have? OH Cl Cl O H O OH O HO O OH Cl

How many chiral centers does Splenda have? nine What is the theoretical maximum number of stereoisomers can this sugar substitute have? 2 n , where n = number of stereogenic groups: 2 9 = 512 OH Cl Cl O H O OH O HO O OH Cl

Are the configurations of Splenda’s indicated chiral centers R or S ? OH Cl Cl O H O OH O HO O OH Cl

Are the configurations of Splenda’s indicated chiral centers R or S ? Cl C Cl O C O H C O R C R O C O C H C H OH C O Cl 1 Cl O 3 H O OH O 2 4 HO O 2 1 3 OH Cl 4

Product distribution studies of the radical chlorination of 2-methylbutane Hydrogens (or any functional groups) that produce the same product are said to be chemically equivalent or homotopic H a H c H c Cl H c H c H d H d H a C C Cl 2 H a C C C C H d C C H d H a ∆ H a C H b H d C H b H a H d H a H a H a H a H a Substitution of any 1 of the six H a results in 1-chloro-2-methybutane 2-methylbutane has a group of six chemically equivalent H a hydrogens Another way of describing this: both of the CH a3 methyl groups are chemically equivalent H a H c H c H c H c H d substituion of CH 3 groups H d H a C C (fun) C by (fun) groups C C H d C C H d H a ∆ C H b H d C H b H a H d H a H a H a H a H a 2-(fun)butane

H a H c H c H a H c H c H d H a C C Cl 2 H d C H a C C C H d H a C C H d ∆ H a C H b H d H a C Cl H d H a H a H a H a H a Substitution of the H b results in 2-chloro-2-methylbutane 2-methylbutane has a group of one chemically equivalent H b hydrogen The H a ’s and H b are not chemically equivalent Chemically nonequivalent functional groups are heterotopic functional groups Cl H c H c H d H a C C C C H d H a C H b H d H a H a H a 1-chloro-2-methylbutane

H a H c H c H a H a Cl H c H c Cl H d H a C C Cl 2 H d H d H a C C H a C C C C H d C H d C C C H d H a ∆ H a H a C H b H d C H b H a C H b H d H d H a H a H a H a H a H a H a H a ( R )-2-chloro-3-methylbutane or ( S )-2-chloro-3-methylbutane Substitution of an H c results in (a racemate) 2-methylbutane has a group of two chemically equivalent H c hydrogens The H c ’s generate stereoisomers upon substititution These stereoisomers are enantiomers Functional groups that make stereoisomeric products are stereotopic groups If these stereoisomers are enantiomers, the functional groups are enantiotopic H a H c H c Cl H c H c H d H a C C H d H a C C C C H d C C H d H a H a C Cl H d H a C H b H d H a H a H a H a H a 1-chloro-2-methylbutane 2-chloro-2-methylbutane

H a H a H c H c H c H c H d H d H a C C Cl 2 H a C C C C H d C C H d H a H a ∆ C H b C H b H d Cl H a H a H a H a H a H a Substitution of an H d results in 1-chloro-3-methylbutane 2-methylbutane has a group of three chemically equivalent H d hydrogens The CH a3 methyl groups and the CH d3 methyl group are not chemically equivalent So, 2-methylbutane has four groups of chemically nonequivalent hydrogens Cl H a H c H c H c H c H a H c Cl H d H d H d H a C C H a C C C H a C C C H d C C H d C C H d H a H a H a C H b C Cl H d H d C H b H a H a H d H a H a H a H a H a H a H a rac -2-chloro-3-methylbutane 1-chloro-2-methylbutane 2-chloro-2-methylbutane

What if a substitution resulted in diastereoisomeric products? H a H c H c H a H a H c Cl Cl H c H d C Cl 2 H a C H d H d C H a C C H a C C C H d C C H d C C H d ∆ H a H a H a F H b H d F H b F H b H d H d ( S )-2-fluorobutane (2 S, 3 S )-2-chloro-3-fluorobutane (2 R, 3 S )-2-chloro-3-fluorobutane ( S )-2-fluorobutane has two chemically nonequivalent H c hydrogens The H c ’s generate stereoisomers upon substititution These stereoisomers are diasteriomers Functional groups that make stereoisomeric products are stereotopic groups If these stereoisomers are diasteriomers, the functional groups are diastereotopic So, ( S )-2-fluorobutane has five chemically nonequivaent groups of hydrogens

Types of groups of hydrogens Chemically equivalent Chemically nonequivalent (homotopic) (heterotopic) generate the same constitutional generate different constitutiona isomer upon substitution isomers upon substitution generate enantiomers upon generate diastereomers upon substitution (enantiotopic) substitution (diastereotopic)