[Nescafe]

Hi,

I am reading contradicting information whether these two forms rotate light differently, I was told the D and L are just to distinguish the two conformations and not how they rotate polarized light, can someone confirm this please?

Cheers,

Nescafe.

[discodermolide]

They are enantiomers and rotate the polarised light in opposite directions. The D & L notation tells you this.
Find out for yourself what the "D" and "L" stand for.

[Babcock_Hall]

Can you define the terms conformation and configuration for us?  That might lead to an answer rather quickly. 

[Dan]

I was told the D and L are just to distinguish the two conformations and not how they rotate polarized light

Check your definitions (Babcock_Hall's post).

I think the confusion may be in the fact that D/L tell you, as discodermolide said, that the compounds are enantiomers (and will rotate polarised light in opposite directions), but D/L does not indicate which direction the light will rotate.

i.e. you could have a D-sugar that rotates (+), and the L enantiomer would be (-); or you could have a D-sugar that is (-), and its L enantiomer would be (+).

You may find this useful:
http://www.chemicalforums.com/index.php?topic=60366.msg215935#msg215935

[Nescafe]

I was told the D and L are just to distinguish the two conformations and not how they rotate polarized light

Check your definitions (Babcock_Hall's post).

I think the confusion may be in the fact that D/L tell you, as discodermolide said, that the compounds are enantiomers (and will rotate polarised light in opposite directions), but D/L does not indicate which direction the light will rotate.

i.e. you could have a D-sugar that rotates (+), and the L enantiomer would be (-); or you could have a D-sugar that is (-), and its L enantiomer would be (+).

You may find this useful:
http://www.chemicalforums.com/index.php?topic=60366.msg215935#msg215935

Thanks all, that makes sense Dan thanks for the link!

Nescafe.