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Regioselective Multicomponent Synthesis of 2,4,6‐Trisubstituted Phenols from Fischer Alkynyl Carbene Complexes
Author(s) -
López Julio,
de la Cruz Fabiola N.,
FloresConde María Inés,
FloresÁlamo Marcos,
Delgado Francisco,
Tamariz Joaquín,
Vázquez Miguel A.
Publication year - 2016
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/ejoc.201501211
Subject(s) - chemistry , regioselectivity , carbene , phenols , cycloaddition , phenol , organic chemistry , medicinal chemistry , reaction conditions , combinatorial chemistry , catalysis
Abstract A series of 2,4,6‐trisubstituted phenols 7a – 7p has been prepared in moderate to good yields (23–77 %) by a retro‐Diels–Alder reaction from hindered tricyclic alcohols 6a – 6q , using mild acidic conditions. The tricyclic alcohols were obtained by reduction of highly functionalized cyclohexadienones 5a – 5q , which in turn were regioselectively prepared under mild conditions in high yields by treatment of a series of stable chromium(0) and tungsten(0) Fischer dienyl carbenes 4a – 4g with different terminal alkynes 3a – 3l . Carbenes 4a – 4g were prepared by a [4+2] cycloaddition of alkynylethoxy carbene complexes 1a – 1g with 1,2,3,4,5‐pentamethylcyclopentadiene ( 2 ). In a complementary route, compounds 5a – 5q were also obtained by a multicomponent reaction in yields similar to those obtained in the multistep process (25–84 %), starting from 1a – 1g , 2 , and 3a – 3l . The phenol products have a wide range of potential applications, and may be useful intermediates for further transformations.