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Cycloaddition Reactions of Phosphorylated 1,2‐Diaza‐1,3‐butadienes with Olefins: Regioselective Synthesis of Pyridazine Derivatives
Author(s) -
Palacios Francisco,
Aparicio Domitila,
López Yago,
de los Santos Jesús M.,
Alonso Concepción
Publication year - 2005
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.200400675
Subject(s) - norbornadiene , chemistry , cyclopentadiene , cycloaddition , regioselectivity , pyridazine , styrene , substituent , bicyclic molecule , medicinal chemistry , norbornene , organic chemistry , catalysis , copolymer , polymer
The aza‐Diels–Alder reaction of 4‐phosphinyl‐ and 4‐phosphonyl‐1,2‐diaza‐1,3‐butadienes with styrene, cyclopentadiene, dihydrofuran and norbornadiene is reported. Monocyclic, bicyclic and polycyclic tetrahydropyridazines containing a phosphane oxide or a phosphonate substituent are obtained. The formation of cycloadducts can be explained by an endo transition state in the cycloaddition process of these heterodienes with styrene, cyclopentadiene, dihydrofuran, and by means of an exo transition state in the case of norbornadiene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)