All Questions
Tagged with stereochemistry cyclohexane
22
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Why the C4 in this 1,3,4,5-substituted Cyclohexanes has a R/S configuration?
(1S,3S,4S,5S)-3,5-dimethoxy-1-phenylcyclohexane-1,4-dithiol.
ChemDraw21 shows the C4 is S configuration. However I think C4 has two same function groups(C3 and C5 are both S configuration; C2-1-6 and ...
- 49
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154
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Calculating energy difference between two 1-4 dimethylcyclohexane conformers
The following question was asked in a quiz at my college
Draw the most stable and least stable chair conformer for 1,4-dimethylcyclohexane and calculate the
energy difference between these two. Given ...
2
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1
answer
161
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Can we always use the planar representation of cycloalkanes instead of their true conformations to study their stereochemistry and chirality?
When I have drawn stereoisomers of substituted cyclohexanes and checked if they are chiral, I typically represent the ring as a planar hexagon and look for symmetry elements. For example, I would use ...
- 335
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Are substituents placed alphabetically in the name of a cycloalkane?
I named this molecule 1,5-diethyl-2-methyl-4-propylcyclohexane. Is this correct? Or should we somehow use the size of the substituents?
- 39
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3
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Why is diequatorial trans-1,2-dimethylcyclohexane more stable than diaxial trans-1,2-dimethylcyclohexane?
Consider diequatorial trans-1,2-dimethylcyclohexane and diaxial trans-1,2-dimethylcyclohexane as shown in the figure below [1, p. 178]. In both compounds, the ring is free of angle strain.
trans-1,2-...
- 237
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1
answer
1k
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Why 5-member rings prefer being cis-fused?
It always bothers me how whenever I am doing practice problems I never got a proper explanation as to why 5-member rings prefer(thermodynamically) being cis- rather than trans-fused( as opposed to ...
- 93
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Number of stereoisomers of 1,3,5-trimethylcyclohexane
When I searched the stereoisomers of 1,3,5-trimethylcyclohexane, I got four structures given below.
I don't get how structures 1 and 2, 3, and 4 are not the same. Could anyone explain?
- 123
3
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2
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793
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Is it correct to look at plane of symmetry in substituted cyclohexane for determining a meso compound?
I read this question and it's answer by @orthocresol. Now, he has written that the compound in question is meso not because there is a plane of symmetry but because of the rapid flipping of the ...
- 1,261
2
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105
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Strains in conformations of cyclohexane
I know some the basic kind of strains that can exist in molecules namely Torsional strain (Vanderwaals' strain), steric strain and angle strain.
Is it possible to associate a particular type of ...
- 797
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182
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Cyclohexane derivative formation of carambolaflavone using a Lewis acid catalyst
The scheme below summarizes the results from a study into the optimum conditions needed for a key step in the synthesis of the proposed structure of carambolaflavone, a natural product that has ...
- 175
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874
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2
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1
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Why does 1,2-dimethylcyclohexane only possess three stereoisomers? [duplicate]
Why does 1,2-dimethylcyclohexane in chair form have only three stereoisomers?
I understand that the trans isomer doesn't possess plane of symmetry and thus it has two stereoisomers. But my book says ...
- 241
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1
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2k
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Help with absolute configuration of a substituted cyclohexane?
How is the absolute configuration decided when it is a cyclohexane and several stereocenters? Up to now we have only worked with simple molecules which are only 1. I believe the stereocenters here are ...
- 119
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How to determine the stereochemistry after elimination of anti-1-bromo-2-methylcyclohexane?
The question is asking for the product and the answer is C.
My expected answer was E. Here's how I tried to solve it:
Since Br (the leaving group) is at the equatorial position, the structure would '...
- 33
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1
answer
2k
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Best chair configuration for trimethylcyclohexane matching a specific Haworth projection?
Which option best depicts trimethylcyclohexane shown in the Haworth projection below?
I thought B because
All the methyl groups are equatorial and equatorial groups are more stable.
All the methyl ...
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