Question

Problem 5.38 Shown below are Newman projection formulas for (RR)-, (S,S)-, and (R.S)-2,3-dichlorobutane. CH, CH, H H H СІ CH, CA Which is which? zing 20 izing 7221 nizing

Answer 1

• For A Newman formula: CH₃ er H UTH d' CH3 For R, S nomenclature there have some basie Rule- 1. Newman projection draw as sawhone prosection 2. Then sawhone projection draw as eclipsed position by notation of any one carbon. 3. Then we easity draw the Fischer projection formula. Newman -→ Fischer: CH3 CH3 d WH A Sawhorse projection transform TH "H CHO Снь CH3 CH3 1 H L Eclipsed formation by back-c notation Fischer projection convent a H ㅗ 3 ah CH3 Rule for Rs-nomenclature of Fischer projection 1. If 4th group is in verticle position 1 2 3 = dockwise =R 4 => anticlockwise =s

2. If 4th group is in horizontal position 1 2 3 => clockwise =s =) Anticlockwise =R CH3 I 2 a numbering acconding to the IUPAC rule. a-3-H. 4 CH₂ For '2' no: chinal centre. CH₂ priority according to CIP rule 6 al 0 ② is in ver Horizontal position 1+2+3 => dockwise = 5 2 a ② is in a eta For 3 no. Chinas centra: 4 is in horizontal position 123 => clockwise=s .. Ais (5,5)-2, 3-diclorobutane

o For B' Newman formula: CH3 I a sawhonse To projection H u 해3 a CH3 for Rotation eclipsed CH3 CH3 CH3 Ta a el- H Fischer projection convent H CH₃ R,S-Nomen datune: t H CHZ 2 H I Rule. Numbening acconding to IUPAC HB-a 4 CH3 For 2 no: chinal centre: B CH3 4th is in Horizontal line H it 12 + 3 => anticlockwisesa ch 6 cita a Fon 3, no.chinal centre: CH3 a 4th is in Horizontal line 1+2+3 => anticlockwise=R SCH i For Newman B'-(R, R)-2,3-dichlorobutane

o For Newman c formula CH3 CH3 Sawhorse H ma H H convert & T Она Y CH3 for Rotation eclipsea CH3 CH3 CH 3 UH Fischer projection a H СА» For R, S - Nomenclature: CH3 a 2 . H According to IUPAC rule. u3H 1 сн» For 2 Chinal carbon 4th is in Horizonal line 1 2 3 => anticlockwise =R (4- 14 ©.at city C

For z chinal centre: Ct3 d. CHO 4th is, in horizontal line D 1+ 23 =) clockwise us 3 Citz in Newman c is CR,S)-2,3-dichlorobutane.