[critzz]

Hi,

So I was wondering about this silly question.
I would consider the structure below chiral, but how does one determine in this case if it's (S) or (R)?

[sjb]

Hi,

So I was wondering about this silly question.
I would consider the structure below chiral, but how does one determine in this case if it's (S) or (R)?

From what I recall, the E double bond has priority over the Z one.

[Dan]

From what I recall, the E double bond has priority over the Z one.

I don't think this is correct. According to Eliel and Wilen:

"the olefinic ligand in which the substituent of higher sequence is on the same side of the olefinic double bond as the chiral center has precedence over the over the ligand in which the substituent of higher sequence is trans to the chiral center"

See also this page, section 3, point 5.

According to this, for the posted compound the Z branch has higher priority.

[sjb]

My mistake, it has been a while. Thanks Dan

[critzz]

Ah I figured it was something like that, thanks.