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Revealing the Origin of Π‐facial and Regioselectivity in the Diels‐Alder Reaction of Unsymmetrical, Cage‐annulated 1,3‐Cyclohexadiene with Ethyl Propiolate Dienophile: a DFT Study
Author(s) -
Patel Tulsi R.,
Ganguly Bishwajit
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202003443
Subject(s) - regioselectivity , chemistry , stereoselectivity , steric effects , diene , diels–alder reaction , covalent bond , computational chemistry , stereochemistry , organic chemistry , catalysis , natural rubber
DFT [M06‐2X/6‐31+G(d,p) and MPWB1 K/6‐311G(d)] calculations have elucidated the origins of π‐facial and regioselectivity in the Diels‐Alder reactions of hexacyclo [7.5.1.0 1,6 .0 6,13 .0 8,12 .0 10,14 ] pentadeca‐2,4‐diene‐7,15‐dione ( HPDD ) and hexacyclo [7.5.2.0 1,6 .0 6,13 .0 8,12 .0 10,14 ] hexadeca‐2,4‐diene‐7,16‐dione ( HHDD ) dienes with ethyl propiolate ( EP ) as the dienophile. The origin of π‐facial stereoselectivity of these Diels‐Alder reactions has been rationalized with molecular electrostatic potential (MESP), potential energy surface (PES), and Non‐Covalent Interaction (NCI). The role of the steric effect on the π‐facial stereoselectivity of these Diels‐Alder reactions has also been observed. The origin of distal/proximal regioselectivity of HHDD with EP was explained by attractive Non‐Covalent Interaction (NCI) and electrostatic repulsion. This is one of the rare examples in Diels‐Alder reaction with both the π‐facial stereoselectivity and the regioselectivity with single diene and dienophile.