Baldwins Rules

Question 1

Baldwins nomenclature

Answer 1

Ring size, endo/exo, geometry at electrophilic atom

Question 2

Outside

Answer 2

Exo

Question 3

Inside

Answer 3

Endo

Question 4

Sp hybridised

Answer 4

Dig

Question 5

Sp2 hybridised

Answer 5

Trig

Question 6

Sp3 hybridised

Answer 6

Têt

Question 7

Tetrahedral angle of attack

Answer 7

180, Sn2

Question 8

Trigonal angle of attack

Answer 8

109, new bond forms to sp3 hybridised C

Question 9

Digonal angle of attack

Answer 9

120, favourable overlap of incoming Nu- with π* orbital of alkyne triple bond

Question 10

Why Baldwins rules

Answer 10

Stereoelectronic effect, favoured cyclisations have good overlap in TS

Question 11

Why exo-tet and exo-trig favoured?

Answer 11

Rotation about C-C bond makes good overlap irrespective of ring size

Question 12

Exceptions to Baldwins rules

Answer 12

Acetal formation, cations, pericyclic reactions and nucleophiles from period 3 elements

Question 13

Why does Sulfur not obey Baldwins rules as a nucleophile?

Answer 13

C-s bonds are long and more diffuse orbitals can overlap with C=C π* orbital, empty 3d of S also have right symmetry to overlap with π* orbital of terminal alkene C’s