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From Osmium Hydrido Vinylidene to Osmacycles: The Key Role of Osmabutadiene Intermediates
Author(s) -
Zhao Qianyi,
Cao XiaoYu,
Wen Ting Bin,
Xia Haiping
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201200872
Subject(s) - osmium , chemistry , reactivity (psychology) , carbon atom , yield (engineering) , medicinal chemistry , carbon fibers , stereochemistry , organic chemistry , catalysis , ruthenium , materials science , alkyl , medicine , alternative medicine , pathology , composite number , metallurgy , composite material
Osmium hydrido vinylidene 1 shows diverse cyclization reactivity with activated terminal alkynes. Treatment of 1 with HCCCOR′ (R′=OEt and Me) gave osmafurans 3 a and 3 b via osmium alkenyl/vinylidenes 2 a and 2 b . In addition, 1 reacted with HCCCH(OH)CCH to yield osmabenzene 4 , in which the alkynol acted as a C 5 fragment to cyclize with 1 . Mechanistic analysis indicates that these reactions and the previous formal [3+3] cycloadditions between 1 and HCCCH(OH)R (R=Ph, Et, and vinyl) or HCCCH(OEt) 2 all go through similar osmabutadiene intermediates. Subsequently, the intermediates either took a “coordination and cyclization” process or a “carbon–carbon coupling” path to cyclization , depending on the coordination ability of substituents on the terminal alkenyl carbon atom.