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Intramolecular Copper‐ and Rhodium‐Mediated Carbenoid Reactions of α‐(Propargyloxy)silyl‐α‐diazoacetates
Author(s) -
Gettwert Volker,
Krebs Fred,
Maas Gerhard
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<1213::aid-ejoc1213>3.0.co;2-u
Subject(s) - chemistry , carbenoid , intramolecular force , rhodium , bicyclic molecule , alkyne , trifluoromethanesulfonate , silylation , copper , medicinal chemistry , cyclopropene , metal , catalysis , stereochemistry , polymer chemistry , organic chemistry
Copper(I) triflate catalyzes the transformation of α‐[(2‐alkynyl)oxy]silyl‐α‐diazoacetates 1a–g into 1,2‐bis(2,5‐dihydro‐1,2‐oxasilol‐4‐yl)ethenes 2 and/or 2 H ‐1,2‐oxasilines 3 . With rhodium(II) perfluorobutyrate as catalyst, 1a–e furnish only 3 but no 2 . Bicyclic 2‐methoxyfurans 6 are formed when 1a , c , e (containing terminal alkyne functions) are treated with catalytic amounts of copper(I) chloride. The experimental observations are explained in terms of metal‐mediated intramolecular cyclopropenation and subsequent metal‐assisted ring‐opening of the strained bicyclic cyclopropene leading to vinylcarbene‐metal complexes. An unusual autoxidation of 2 H ‐1,2‐oxasilines 3a , c , e is also described.