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Neue Bi(cyclopropylidene) durch CuCl 2 ‐katalysierte ‘Carben‐Dimerisieiung’ von 1‐Bromo‐1‐lithiocyclopropanen
Author(s) -
Borer Markus,
Neuenschwander Markus
Publication year - 1997
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19970800816
Subject(s) - chemistry , carbene , table (database) , reaction mechanism , simple (philosophy) , medicinal chemistry , kinetic energy , reaction conditions , stereochemistry , catalysis , organic chemistry , philosophy , physics , epistemology , quantum mechanics , computer science , data mining
New Bi(cyclopropylidenes) by CuCl 2 ‐Induced ‘Carbene Dimerization’ of 1‐Bromo‐1‐lithiocycIopropanes A series of so far unknown bi(cyclopropylidenes) 5 are prepared in a simple one‐pot reaction by halogenolithio exchange between 1,1‐dibromocyclopropanes 1a – c as well as 1e – i and BuLi at −95°, to give 1‐bromo‐1‐lithiocyclopropanes 2a – c as well as 2e – i , followed by treatment with CuCl 2 at low temperature and a simple workup at room temperature ( Table 1 ). The influence of reaction parameters on yields of 5 ( Tables 2, 4 , and 5 ) and diastereoselectivity of the reaction 2 → 5 ( Table 3 ) are discussed. In view of an elucidation of the reaction mechanism, first kinetic experiments of the quantitative reaction 1c → 2c → 5c are reported.