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On the Behavior of 5,8‐Bis(trimethylsilyl)cycloocta‐1,3,6‐triene in Cycloaddition Reactions and Subsequent Chemistry
Author(s) -
Hofmann Michael A.,
Nachbauer Anja,
Bergsträßer Uwe,
Regitz Manfred
Publication year - 1999
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/(sici)1099-0690(199905)1999:5<1041::aid-ejoc1041>3.0.co;2-b
Subject(s) - chemistry , cyclobutene , cycloaddition , trimethylsilyl , diels–alder reaction , adduct , bicyclic molecule , medicinal chemistry , stereochemistry , organic chemistry , ring (chemistry) , catalysis
Phosphaalkynes 2 and electron‐deficient alkynes 11 readily react in a [4 + 2] cycloaddition process with 5,8‐bis(trimethylsilyl)cycloocta‐1,3,6‐triene ( 8 ) in its bicyclic form 10 to furnish regioselectively the tricyclodecadienes 12 and 13 , respectively. The phosphorus‐containing compounds 12 exhibit structural features which make them suitable for homo‐Diels–Alder reactions with electron‐deficient acetylenes. A single crystal structure analysis of the homo‐Diels–Alder adduct 14b confirmed the structure and relative configuration of the phophatricyclodecadienes 12 . In solution the tricyclodecadienes 13 are prone to facile cycloreversion yielding the phthalic esters 15 and the cyclobutene 16 . The latter is rapidly converted into the corresponding 1,3‐butadiene 18 , which can be trapped in a Diels–Alder/phospha‐ene/Diels–Alder tandem reaction sequence by phosphaalkyne 2a . The phosphatricyclodecadiene 12 is thermally more stable; loss of cyclobutene 16 only occurs under FVP conditions to afford the λ 3 ‐phosphinine 22 .