Unusual reactivity of upper-rim bridged calix[4]arenes – Friedel–Crafts alkylation via cleavage of the macrocyclic skeleton

TY - JOUR

T1 - Unusual reactivity of upper-rim bridged calix[4]arenes – Friedel–Crafts alkylation via cleavage of the macrocyclic skeleton

AU - Slavík, Petr

AU - Lhoták, Pavel

PY - 2018/5/2

Y1 - 2018/5/2

N2 - Upper-rim bridged derivatives of calix[4]arenes, prepared by the direct introduction of mercury into the meta position of the basic skeleton followed by Pd-catalyzed intramolecular bridging, represent a novel type of calixarenes bearing an additional single bond between the meta positions of neighboring aromatic units. Due to the presence of this short bridge, these compounds exhibit extremely distorted cavities when compared with common calix[4]arenes. As a consequence of highly enhanced inner strain, the bridged compounds can be cleaved under acidic conditions to form open oligomeric species (benzylic type carbocation) that can be used for the Friedel–Crafts alkylation of aromatic compounds. This behavior, never observed in common calix[4]arenes, demonstrates a reasonably amended reactivity invoked by the additional bridge.

AB - Upper-rim bridged derivatives of calix[4]arenes, prepared by the direct introduction of mercury into the meta position of the basic skeleton followed by Pd-catalyzed intramolecular bridging, represent a novel type of calixarenes bearing an additional single bond between the meta positions of neighboring aromatic units. Due to the presence of this short bridge, these compounds exhibit extremely distorted cavities when compared with common calix[4]arenes. As a consequence of highly enhanced inner strain, the bridged compounds can be cleaved under acidic conditions to form open oligomeric species (benzylic type carbocation) that can be used for the Friedel–Crafts alkylation of aromatic compounds. This behavior, never observed in common calix[4]arenes, demonstrates a reasonably amended reactivity invoked by the additional bridge.

KW - Bridging

KW - Calix[4]arene

KW - Cleavage

KW - Friedel-Crafts alkylation

KW - Mercuration

UR - http://www.scopus.com/inward/record.url?scp=85044955132&partnerID=8YFLogxK

U2 - 10.1016/j.tetlet.2018.03.072

DO - 10.1016/j.tetlet.2018.03.072

M3 - Article

AN - SCOPUS:85044955132

SN - 0040-4039

VL - 59

SP - 1757

EP - 1759

JO - Tetrahedron Letters

JF - Tetrahedron Letters

IS - 18

ER -