[hasankamal007]

Hello,
Can you help me and answer following questions regarding the compound in the attached image(THE PRODUCT OF THE REACTION SHOWN IN IMAGE)

• How can I know if this compound is optically active?(i.e. chiral)
  What is the best way to do this?
• Suppose, I choose to draw this compound's Fischer Projection, How should I be doing it?
  Note:The problem I'm having when I try to draw its Fischer Projection is this:
  I look at the compound from above(point A in image) and I see
  Carbon#2 - CH3 and H coming towards me
  Carbon#3 - Only Br coming towards me

Now, the problem is that in Fischer projections,
horizontal lines convey left and right(i.e. two) substituents coming towards viewer. But Chiral Carbon#3 shows only one Br coming out towards viewer.
So how should I draw it? Should I rotate the Carbon#3 about C2-C3 bond so that two substituents start pointing towards it? Is that allowed?
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Thank you.

[Babcock_Hall]

Rotations around single bonds are allowed. Fischer projections are drawn in the eclipsed conformation.

[hasankamal007]

Rotations around single bonds are allowed. Fischer projections are drawn in the eclipsed conformation.

Thank you for your answer.

• But, In the 'Staggered' configuration shown in the image the two Br atoms are oppositely(anti-addition on halogenation) placed.
• Now if I rotate this configuration so that I'm able to draw its Fischer projection I would be bringing closer the two Br atoms.
• For eg. If I rotate Carbon#3 about C2-C3 bond anti-clockwise so that  C-3 Hydrogen is opposite to C-2's Br atom, The Br's would be closer than before.

So, would it not defy the anti-addition reaction mechanism of halogenation on alkene ?

Moreover, If I rotate the compound even more so that the two Br's are exactly face-to-face each other(By rotating the shown Newman projection by 180deg) resulting conformation would be eclipsed and I'll be able to draw its Fischer projection but again,
Will it not defy the anti-addition reaction mechanism of halogenation on alkene?

[Babcock_Hall]

The Fischer projection is a convention for displaying a molecule that follows certain rules.  It is not meant to describe the molecule in its lowest energy conformation, for example.