baldwinsrules - BALDWIN'S RULES FOR RING CLOSURE Baldwin's...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
BALDWIN'S RULES FOR RING CLOSURE 135 Baldwin's Rules (Suggestions) for Ring Closure JOC 1977 , 42 , 3846 JCSCC 1976 , 734, 736, 738 Approach Vector Analysis - for an S N 2 displacement at a tetrahedral center, the approach vector of the entering nucleophile is 180° from the departing leaving group L Nu: L Nu Nu :L - for the addition of a nucleophile to an Sp2 center, the nucleophile approaches perpendicular to the π -system. Nu Nu Nomenclature 1. indicate ring size being formed 3 membered ring = 3 4 membered ring = 4 etc. 2. indicate geometry of electrophilic atom if Y= Sp3 center; then Tet (tetrahedral) if Y= Sp2 center; then Trig (trigonal) if Y= Sp center; then Dig (digonal) Y Z X: 3. indicate where displaced electrons end up - if the displaced electron pair ends up out side the ring being formed; then Exo - if the displaced electron pair ends up within the ring being formed; then Endo Y Z X: Exo Z Y X: Endo
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BALDWIN'S RULES FOR RING CLOSURE 136 4. Ring forming reaction is designated as Favored or Disfavored disfavored does not imply the reaction can't or won't occur- it only means the reaction is more difficult than favored reactions. Rules (Suggestions) for Ring Closure - All Exo-Tet reactions are favored X: Y Z X: Y Z X: Y Z X: Y Z X: Y Z 3- 4- 5-
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern