sterochemistry

• what is a constitutional isomer?

  structural isomer
• what are the two types of stereoisomer?


  enantiomers, diastereoisomers
• what is a stereoisomer?

  same formula and connectivity, but differ in the way the atoms are arranged in space
• what is a diastereoisomer?


  stereoisomers that are not mirror images
• what are enantiomers?


  two stereoisomers that are mirror images of each
• what are the properties of enatiomers?


  same physical properties but show equal and opposite optical activity
• what is a cis bond?

  substituents on same side of double bond
• what is a trans isomer?


  substituent are on opposite sides of double bonds
• how do you have cis and trans isomers with cycloalkanes?

  C-C bonds that are constrained,

  cis = both groups are above or below the plane

  trans = one points above the other points below the plane
• what is the difference between Z/E and Cis/trans?

  Z/E is absolute based on higher priority groups on the same side

  but Cis/trans is relative you can say one is cis to the other
• how to calculate priority for E/Z?


  higher atomic mass

  if the bonded group that forms multiple bonds with an adjacent atom take priority
• How to distinguish chiral centres?

  priority group, R and S
• which way does R go?

  Clockwise
• what is anticlockwise?


  S
• what needs to be true for R and S?

  lowest constituent needs to be pointing away
• what is racemic?


  mixture of enantiomers in equal proportion
• how to increase one enatiomer?

  make both reactant chiral
• what is a diasteroisomer?


  Stereoisomer based on multiple chiral centers