Heck-type reactions of allylic alcohols (original) (raw)
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Angewandte Chemie International Edition, 2009
Dedicated to Professor Gerd Meyer on the occasion of his 60th birthday Palladium-catalyzed transformations are of immense importance in modern organic synthesis, especially for C À C bond formation. Prominent examples are, among many others, the Heck reaction [2] and the Stille cross-coupling, [3] which both enjoy frequent application in the synthesis of complex organic molecules. In the course of our research aimed at the synthesis of the antibiotic pestalone (1), we recently attempted to prepare compound 3 from the iodobromobenzaldehyde 2 by palladium-catalyzed Stille cross-coupling using allyltributylstannane (Scheme 1). However, the NMR data of the sole product did not correspond to those expected for 3. Instead, the isomeric indanol rac-4 had formed as was unambiguously confirmed by X-ray crystallography ).
ChemInform, 2006
Through the use of [PdCl(C 3 H 5 )] 2 /cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction using 2-or 3-subtituted allylic alcohols. With these sterically congested alkenes, the selective formation of b-aryl ketones was observed when appropriate reaction conditions were used. The influence of the functional group on the aryl bromide and of the base on the selectivity is remarkable. With several substrates, much higher selectivities were obtained using NaHCO 3 instead of K 2 CO 3 as base. Furthermore, this catalyst can be used at low loading with several substrates. q
Tetrahedron, 2006
Through the use of [PdCl(C 3 H 5 )] 2 /cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction using 2-or 3-subtituted allylic alcohols. With these sterically congested alkenes, the selective formation of b-aryl ketones was observed when appropriate reaction conditions were used. The influence of the functional group on the aryl bromide and of the base on the selectivity is remarkable. With several substrates, much higher selectivities were obtained using NaHCO 3 instead of K 2 CO 3 as base. Furthermore, this catalyst can be used at low loading with several substrates. q