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Chromium‐Templated Synthesis of Densely Substituted Distorted Arenes − Intramolecular Benzannulation of [(Alkynylaryl)alkenyl]carbene Complexes to Planar‐Chiral Hydroquinoid [2.2]Heterametacyclophanes
Author(s) -
Dötz K. H.,
Mittenzwey S.
Publication year - 2002
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 - 10.1002/1099-0690(20021)2002:1<39::aid-ejoc39>3.0.co;2-9
Subject(s) - carbene , chemistry , intramolecular force , chromium , tetrahydrofuran , lithium (medication) , stereochemistry , medicinal chemistry , organic chemistry , solvent , catalysis , medicine , endocrinology
{[( meta ‐Alkynylphenyl)alkenyl]carbene}chromium compounds 1 and 2 have been synthesized by four‐step (or five‐step) and seven‐step sequences, starting from 3‐halophenol or 3‐haloaniline, respectively. This approach, involving high‐yielding Takai reactions and lithium cuprate additions, provides a novel and straightforward route to [(alkynylaryl)alkenyl](methoxy)carbene complexes. Upon gentle warming in tetrahydrofuran, (carbene)chromium compounds of this type undergo intramolecular benzannulation to give novel [2.2]heterametacyclophanes 21 and 22 , bearing two chiral planes arising from the unsymmetrical substitution patterns both of the cyclophane skeleton and of the newly formed, Cr(CO) 3 ‐coordinated benzohydroquinone deck.