
TY  - JOUR
A1  - Christie, RM 
A1  - Rickards, RW 
A1  - Schmalzl, KJ 
A1  - Taylor, D 
T1  - Ring contraction of 4-substituted 2,6-dichlorophenols. The crystal structure of 2,2,4&#945;,5&#945;-Tetrachloro-1&#945;,3&#945;-dihydroxycyclopentane-1,4-carbolactone
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1977
VL  - 30
IS  - 10
SP  - 2195
EP  - 2204
KW  - 
UR  - https://doi.org/10.1071/CH9772195 
N2  - Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4&#945;- alkyl-2,2,5&#945;-trichloro-1&#945;,3&#945;-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4&#945;,5&#945;-tetrachloro-1&#945;,3&#945;-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) &#506;, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/&#963;(I) &#8805; 3.0). 
ER  -

