A second Norrish reaction then adds another C C bond to alcohol "'23 "'and having served its purpose the phenoxy tail is removed in several steps : a Birch reduction to diol "'24 "', oxidation with pyridinium chlorochromate to ketoaldehyde "'25 "'and a reverse Claisen condensation to ketone "'26 " '.
22.
A classical organic synthesis of this compound starts from a Birch reduction of naphthalene to tetrahydronaphthalene ( or isotetralin ), is followed by carbene addition of dichlorocarbene ( prepared in-situ from chloroform and the potassium salt of " tert "-butanol ) followed by a second organic reduction that removes the chloride substituents and is concluded by the organic oxidation by 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone ( DDQ ).
