ORGANOMETALLIC COMPOUNDS 347 (b) The electronegativity of magnesium(1. 2)is less than that of zinc(1.6).( CH3)2,Mg therefore has a more polar carbon-metal bond than( CH3),Zn (c) In this part of the problem two Grignard reagents are compared. Magnesium is the metal in both cases. The difference is the hybridization state of carbon. The sp-hybridized carbon in HCECMgBr is more electronegative than the sp-hybridized carbon in CHCH, Mg Br, and HCECMgBr has a more polar carbon-magnesium bond. 14.17(a) CH, CH, CH, Br 2Li diethyl ether CH CH CHLi LiBr Propyllithium (b) CH, CH, CH, Br Mg diethyl ether CH,CH,CH, MgBr 1-Bromopropane (c) CH CHCH 2Li diethyl ether, CH,CHCH, +Lil propyllithiu (d) CH, CHCH,+Mg CH CHCH Mgl 2-lodopropane (e) 2CH, CHCH,Li Cul (CH CH2CH2)cUlI Propyllithium Lithium dipropylcuprate (f)(CH, CH,CH,), CuLi CH_ CH, CH, CH, Br CHaCH,CHCH,CH,CH,CH Lithium dipropylcuprat 1-Bromobutane CH, CH,CH3 8)(CH,CH,CH,),CuLi+ Lithium dipropylcuprate iodobenzene Propylbenzene h) CH,CH, CH,Mg BI D CH3 D Propylmagnesium I-Deuteriopropane (i) CH,CHCH CH, CHCH 2-Deuteriopro ( CH,CH,CH, Li + HCH diethyl ether CH CHCHCH OH ropyllithium 1-Butanol Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website
(b) The electronegativity of magnesium (1.2) is less than that of zinc (1.6). (CH3)2Mg therefore has a more polar carbon–metal bond than (CH3)2Zn. (c) In this part of the problem two Grignard reagents are compared. Magnesium is the metal in both cases. The difference is the hybridization state of carbon. The sp-hybridized carbon in HC>CMgBr is more electronegative than the sp3 -hybridized carbon in CH3CH2MgBr, and HC>CMgBr has a more polar carbon–magnesium bond. 14.17 (a) (b) (c) (d) (e) ( f ) (g) (h) (i) ( j) 1. diethyl ether 2. H3O Propyllithium CH3CH2CH2Li 1-Butanol HCH CH3CH2CH2CH2OH O D2O DCl Isopropyllithium CH3CHCH3 Li 2-Deuteriopropane CH3CHCH3 D Propylmagnesium bromide CH3CH2CH2MgBr 1-Deuteriopropane CH3CH2CH2D D2O DCl Lithium dipropylcuprate Iodobenzene Propylbenzene (CH3CH2CH2)2CuLi I CH2CH2CH3 Heptane CH3CH2CH2CH2Br CH3CH2CH2CH2CH2CH2CH3 Lithium dipropylcuprate 1-Bromobutane (CH3CH2CH2)2CuLi CuI Propyllithium 2CH3CH2CH2Li Lithium dipropylcuprate (CH3CH2CH2)2CuLi diethyl ether Mg 2-Iodopropane Isopropylmagnesium iodide MgI CH3CHCH3 CH3CHCH3 I diethyl ether 2Li 2-Iodopropane CH3CHCH3 LiI Isopropyllithium Li CH3CHCH3 I diethyl ether Mg 1-Bromopropane CH3CH2CH2Br Propylmagnesium bromide CH3CH2CH2MgBr diethyl ether 2Li 1-Bromopropane CH3CH2CH2Br LiBr Propyllithium CH3CH2CH2Li ORGANOMETALLIC COMPOUNDS 347 Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website
348 ORGANOMETALLIC COMPOUNDS () CH_ CH_CH2MgBr CH 1.diethyl ether CHCHCHCH 2.H.0 opylmagnesium 1-Phenyl-1-butanol 1. diethyl ethe () CH; CHCH3+ (CH3),CH OH Isopropyllithium cycloheptanone (m) CH, CHCH, CH CCHChs 2,go CHCH-CCHCH Mgl CH3 CH3 isopropyl magnesium iodide (n) 2CH,CH, CH,MgBr CBH_ COCH I diethyl et C6H5C(CH, CH, CH3)2 CH,OH Propylmagnesit Methyl benzoate 4-Phenyl-4-heptanol bromide CHAL (o) H2C=CH(CH2)5CH3 Znic Zn(Cu), diethyl ether H,C-CH(CH,)SCH3 1-Octene H,C CH, L, Zn(Cu), diethyl (CH,) CH H(CH,)CH3 (Er-2-Decene trans-1-Heptyl-2 CH,CH (CH2) CH H,1 CHCH2i CH,I-CE Zn(Cu), diethyl ether HH (Z)-3-Decene (r) HC=CHCH CH,CH, KOc(CH : H"kaC CHCh CH 1-Pentene 1. 1-Dibromo-2-propylcyclopropane 14.18 In the solutions to this problem, the Grignard reagent butylmagnesium bromide is used In each case the use of butyllithium would be equally satisfactory Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website
(k) (l) (m) (n) (o) (p) (q) (r) 14.18 In the solutions to this problem, the Grignard reagent butylmagnesium bromide is used. In each case the use of butyllithium would be equally satisfactory. 1-Pentene H2C CHCH2CH2CH3 CHBr3 KOC(CH3)3 1,1-Dibromo-2-propylcyclopropane H CH2CH2CH3 H H Br Br cis-1-Ethyl-2-hexylcyclopropane CH2I2 Zn(Cu), diethyl ether C C H CH3CH2 H (CH2)5CH3 (Z)-3-Decene CH3CH2 (CH2)5CH3 H H trans-1-Heptyl-2- methylcyclopropane CH2I2 Zn(Cu), diethyl ether C C H H3C (CH2)6CH3 H (E)-2-Decene H3C H H (CH2)6CH3 CH2I2 1-Octene Zn(Cu), diethyl ether 1-Cyclopropylhexane H2C CH2 CH(CH2) CH(CH2 5CH3 ) H2C 5CH3 2CH3CH2CH2MgBr Propylmagnesium bromide Methyl benzoate C6H5COCH3 O 1. diethyl ether 2. H3O 4-Phenyl-4-heptanol C6H5C(CH2CH2CH3)2 CH3OH OH Methanol 2-Butanone CH3CCH2CH3 O 1. diethyl ether 2. H3O 2,3-Dimethyl-3-pentanol CH3CH CCH2CH3 OH CH3 CH3 Isopropylmagnesium iodide CH3CHCH3 MgI Isopropyllithium CH3CHCH3 Li 1. diethyl ether 2. H3O Cycloheptanone O 1-Isopropylcycloheptanol (CH3)2CH OH Propylmagnesium bromide CH3CH2CH2MgBr Benzaldehyde CH O 1-Phenyl-1-butanol CHCH2CH2CH3 OH 1. diethyl ether 2. H3O 348 ORGANOMETALLIC COMPOUNDS Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website
ORGANOMETALLIC COMPOUNDS 349 (a) 1-Pentanol is a primary alcohol having one more carbon atom than 1-bromobutane. Retrosyn- thetic analysis suggests the reaction of a Grignard reagent with formaldehyde CH,CHCH,CH,+CH,OH CH CH, CH,CH Mgx HC=( 1-Pentanol Butylmagnesium halid Formaldehyde An appropriate synthetic scheme is CH3 CH,CH,CH, Br CHa CH,CH,CH,MgBr CH3 CH, CH,CH,CH,OH 1-Pentanol (b) 2-Hexanol is a secondary alcohol having two more carbon atoms than l-bromobutane vealed by retrosynthetic analysis, it may be prepared by reaction of ethanal(acetaldeh ith butylmagnesium bromide CHCHCH,,+CHCH,> CHCH,,Mgx + CHCH OH 2-Hexanol Buty magnesium halide acetaldehyde The correct reaction sequence is I CH,CH CHaCH,CH, BI CHa,CH, CH, MgBr H CHCH..CHCH diethyl ether Butylmagnesium bromide 2-Hexanol (c) 1-Phenyl-l-pentanol is a secondary alcohol Disconnection suggests that it can be prepared from butylmagnesium bromide and an aldehyde; benzaldehyde is the appropriate aldehyde CH,CH, CH, CH,+CH CHaCH,CHCH,Mgx+ I-Phenyl-l-pentanol Butylmagnesium halide Benzaldehyde CHa,CHLCH, Mg Br Fo CHCHCHCHCH Butylmagnesium bromide (d) The target molecule 3-methyl-3-heptanol has the structure CH CH CHCHCH CH, CH3 Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website
(a) 1-Pentanol is a primary alcohol having one more carbon atom than 1-bromobutane. Retrosynthetic analysis suggests the reaction of a Grignard reagent with formaldehyde. An appropriate synthetic scheme is (b) 2-Hexanol is a secondary alcohol having two more carbon atoms than 1-bromobutane. As revealed by retrosynthetic analysis, it may be prepared by reaction of ethanal (acetaldehyde) with butylmagnesium bromide. The correct reaction sequence is (c) 1-Phenyl-1-pentanol is a secondary alcohol. Disconnection suggests that it can be prepared from butylmagnesium bromide and an aldehyde; benzaldehyde is the appropriate aldehyde. (d) The target molecule 3-methyl-3-heptanol has the structure C OH CH3 CH3CH2CH2CH2 CH2CH3 1. ether 2. H3O Benzaldehyde CH O 1-Phenyl-1-pentanol CHCH2CH2CH2CH3 OH CH3CH2CH2CH2MgBr Butylmagnesium bromide Butylmagnesium halide CH3CH2CH2CH2MgX 1-Phenyl-1-pentanol CH3CH2CH2CH2 CH OH Benzaldehyde CH O CH3CH2CH2CH2Br 1-Bromobutane Butylmagnesium bromide CH3CH2CH2CH2MgBr 2-Hexanol CH3CH2CH2CH2CHCH3 OH Mg diethyl ether 2. H3O 1. CH3CH O 2-Hexanol Butylmagnesium halide Ethanal (acetaldehyde) CH3CH2CH2CH2MgX CH3CH O CH3CH2CH2CH2 CHCH3 OH CH3CH2CH2CH2Br 1-Bromobutane Mg diethyl ether Butylmagnesium bromide CH3CH2CH2CH2MgBr CH3CH2CH2CH2CH2OH 1-Pentanol 2. H3O 1. HCH O CH3CH2CH2CH2 1-Pentanol Butylmagnesium halide Formaldehyde CH2OH O CH3CH2CH2CH2MgX H2C ORGANOMETALLIC COMPOUNDS 349 Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website