Question

os structures are show cand trans molecules srent sequence of groups ul (CH3) group and les initially, a-CH- ction gives, initially, a aded to four different 1,2-Disubstituted Cyclohexanes Now consider 1,2-dimethylcyclohexane. The cis and trans in Fig. 5-21. C-1 and C-2 are both stereocenters in the cis and Going around the ring in either direction gives a different seg Start at either of the carbon atoms bonded to a methyl (-CH hydrogen atom. Going around the ring in one direction gives, initi group and going around the ring in the opposite direction give --CH(CH3)- group. Each carbon atom (C-1 and C-2) is bonded to fo groups and each is a stereocenter. Does the cis or trans isomer have a plane of symmetry? The cise has a plane of symmetry, as shown in Fig. 5-21. A plane perpendicu ring bisecting the bonds between C-1 and C-2 and C-4 and C-5 is a mir So the cis compound is achiral even though it contains two stereocent meso compound. There is no mirror plane in the trans compound. One the mirror plane has the methyl group "above" the ring and the other side of The cis compour erpendicular to t e the 2 CH3 CH₂ CH: CH3 CH3 CHE How are the 2 Stereocenters? Plane of symmetry- Not a plane of symmetry cis trans trans The mirror images are not superimposible Fig. 5-21. cis- and trans-1,2-Dimethylcyclohexane.
how does the structure on thr bottom left have 2 stereocenters? I see both Carbons in the CH3 being bonded directly to a H, -CH2 and another -CH3. i do not see how there are 4 different groups that each chiral carbon is attached to

Answer 1

1,2-disubstituted cyclohexane cis form of 1,2, dimethyl cyclohexane и си, си; M Or Both carbon 1 and 2 are stereocentser, because it has four different groups. at . Ca a CH3 group about the plane s H group down the plane n y on the right side at C2 there is the ius -CH(CH3 )– group. s on the left side at co there is a cha 1 group. since -CH(CH3)- and -CH₂- are different group also it and CH3 all your are distinct thats why C is a chiral carbon Similarly C2. is also a chiral carbon But whole compound is meso ie optically inactive. because it has plani of symmetry.