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Preparation of phenyl substituted propargylic alcohol dicobalt hexacarbonyls and their reactions with active methylene compounds in the presence of acid
Author(s) -
Sun ShouHeng,
Chen WeiBing,
Zhang WenWei,
Li DongWen,
Meng QingJin,
You XiaoZeng
Publication year - 1992
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19920100105
Subject(s) - chemistry , methylene , alcohol , dichloromethane , phosphorus pentoxide , alkylation , medicinal chemistry , dehydration , alkyl , dehydration reaction , methanol , organic chemistry , conjugated system , ethanol , catalysis , solvent , biochemistry , polymer
Abstract Eight new complexes with the formula [PhC 2 C(OH)R 1 R 2 ]Co 2 (CO) 4 were prepared from phenyl substituted propargylic alcohols and dicobalt octacarbonyl. The reactions of these propargylic alcohol complexes with active methylene compounds, 2,4‐pentanedione or ethyl acetoacetate, in the presence of an acid, HBF 4 (40%) + P 2 O 5 (in excess) or BF 2 ·Et 2 O, at room temperature in dichloromethane were investigated. From the 1‐alkyl substituted tertiary propargylic alcohol complexes, three new conjugated ene‐yne complexes produced by intramolecular dehydration reaction were isolated in high yields (82–95%). On the other hand, four new alkylated complexes were obtained with satisfactory yields (44–66%) from the secondary propargylic alcohol complexes. The influence of other acids, phosphorus pentoxide and polyphosphoric acid, on both dehydration reaction and alkylated reaction was also studied.