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Lithiation of 2‐Aryl‐2‐(chloroaryl)‐1,3‐dioxolanes and Its Application in the Synthesis of New ortho ‐Functionalized Benzophenone Derivatives
Author(s) -
Lukács Gyula,
PorcsMakkay Márta,
Simig Gyula
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400335
Subject(s) - benzophenone , chemistry , aryl , electrophile , substituent , intramolecular force , deprotonation , ring (chemistry) , medicinal chemistry , ketone , stereochemistry , organic chemistry , catalysis , ion , alkyl
Abstract 2‐Aryl‐2‐(chloroaryl)‐1,3‐dioxolanes 4 were lithiated ortho to the ketal group of the chloroaryl ring by treatment with butyllithium in THF between −78 and 0 °C. The site selectivity of some of the deprotonation reactions was rationalized by the long‐range effect of the 4‐chloro substituent. The lithio species thus generated were treated with various electrophiles to give ortho ‐functionalized benzophenone derivatives. Intramolecular competition between the aryl rings was observed in the lithiation of 2‐(4‐chlorophenyl)‐2‐(4‐fluorophenyl)‐1,3‐dioxolane ( 4s ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)