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Regioselektive Substitution an [2.2]Metacyclophanen via Chromtricarbonyl‐Komplexe
Author(s) -
Vögtle Fritz,
Schulz Jürgen,
Nieger Martin
Publication year - 1991
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19911240616
Subject(s) - chemistry , regioselectivity , steric effects , substitution (logic) , electrophilic substitution , chromium , substitution reaction , stereochemistry , electrophilic aromatic substitution , crystal structure , electrophile , medicinal chemistry , crystallography , catalysis , organic chemistry , computer science , programming language
Regioselective Substitution of [2.2]Metacyclophanes via Chromium Tricarbonyl Complexes The [2.2]metacyclophanes 6, 8 , and 9 are regioselectively complexed with triammintricarbonylchromium. The complexes are lithiated with n BuLi/TMEDA at –78°C, and the resulting aryllithium complexes are trapped with electrophiles to give new phanes exhibiting substitution patterns, which are not or more difficult available by other routes. Complex 6a gives 5‐substitution almost exclusively, while the chiral complex 8a is substituted in positions 5 and 4 in a ratio of 3:1. Steric effects, caused by the large dithiane group, seem to play a role in both complexation and derivatisation of these substrates. An X‐ray crystal structure analysis of the chromium tricarbonyl phane complex 11 is performed.