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Functionalized Azamacrocycles and Large‐Ring α‐Amino Esters by One‐Pot Syntheses from Methyl 2‐Siloxy‐2‐vinylcyclopropanecarboxylates
Author(s) -
Patra Pranab K.,
Reißig HansUlrich
Publication year - 2001
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(200111)2001:22<4195::aid-ejoc4195>3.0.co;2-3
Subject(s) - chemistry , synthon , ring (chemistry) , alkylation , pyridine , fluoride , derivative (finance) , medicinal chemistry , organic chemistry , combinatorial chemistry , stereochemistry , catalysis , inorganic chemistry , financial economics , economics
Siloxycyclopropane 1 served as starting material for intermediate alkylation products 2 , 7 , 11 , 14 , and 17 , which were elongated to provide a variety of precursor compounds bearing terminal N ‐benzyl groups. These substrates were subjected to a cesium fluoride‐promoted ring‐opening/ring‐closure sequence to afford azamacrocycles 19 , 21 , 22 , 23 , 25 , 26 , 27 , and 28 in moderate to good yields. The cyclic products have different ring sizes and numbers of nitrogen atoms, and may incorporate meta ‐substituted benzene or pyridine units. A second approach employed glycine derivative 29 as the key building block for construction of precursors 31 and 34 , which on fluoride treatment furnished macrocyclic α‐amino esters 32 and 35 , respectively, in moderate yields. A few reactions, such as transformations into macrocyclic pyridazinone derivatives 37 and 38 , illustrate the potential of the synthesized azamacrocycles for preparation of complex compounds. Our concept for construction of macrocyclic compounds using siloxycyclopropane 1 as zwitterionic synthon A has thus successfully been extended to the synthesis of a variety of highly functionalized azamacrocycles.