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Functionalisation of the 1‐Phosphanorbornadiene Structure at the C2 Position by Stille Cross‐Coupling Reactions
Author(s) -
Mouriès Virginie,
Mercier François,
Ricard Louis,
Mathey François
Publication year - 1998
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(199811)1998:11<2683::aid-ejoc2683>3.0.co;2-a
Subject(s) - stille reaction , chemistry , coupling reaction , stereochemistry , coupling (piping) , organic chemistry , polymer , catalysis , mechanical engineering , engineering
The reaction of alkynylstannanes with 1‐phenyl‐3,4‐dimethylphosphole at 150 °C affords the corresponding 2‐stannyl‐1‐phosphanorbornadienes ( 2a, b ), in fair yield. Oxidation under mild conditions affords the corresponding phosphane oxides ( 3a, b ), whereas more drastic conditions (H 2 O 2 , 15% in toluene at 80 °C) induce the oxidative cleavage of the P‐CH 2 bond of the bridge to give a bicyclic phosphinate such as 4 . Treatement of 4 by iodine leads to a tin → iodine exchange. The X‐ray crystal structure analysis of the resulting 1‐phospha‐2‐oxabicyclo[2.2.2]octa‐5,7‐diene 1‐oxide confirms the functionalisation at the α‐position and the relief of ring strain taking place upon insertion of oxygen into the P‐CH 2 bond of the norbornadiene. The 2‐stannyl‐1‐phosphanorbornadiene 1‐oxides ( 3a, b ) readily undergo tin → iodine exchange. The resulting 2‐iodo derivatives ( 6a, b ) can be cross‐coupled with 2‐furyl‐, 2‐thienyl‐, 2‐pyrrolyl‐, phenylethynyl‐, and vinyl‐tributylstannanes to give the corresponding 2‐functional 1‐phosphanorbornadiene 1‐oxides in excellent yields (80‐95%)