chapter 16 conjugated pi systems and pericyclic reactions

stability of compounds with pi bonds

allene < terminal alkyne < internal alkyne < isolated diene < conjugated diene

1,2 and 1,4 addition to conjugated dienes

HBr or other strong acid

how to get 1,2 addition as the major product

HX and 0 degrees

how to get 1,4 as the major product

HX, 40 degrees

how to convert 1,2 product into 1,4 product

heat at 40 degrees

making a conjugated diene from an allylic halide or a dihalide

t-buOK or other sterically hindered base

complete reduction of a diene to get an alkane

2 eq. H2, cat. Pt

diels-alder reaction / 4+2 cycloaddition

diene and a dienophile in close proximity, and diene has to be able to assume an s-cis conformation

SN2 prime

weak base/strong nucleophile that attacks the side of the alkene furthest from the leaving group