esters to terminalalkynes can be switched by the choice of phosphorus ligands on the palladium catalysts. The silaboration proceeds with normal regioselectivity in the presence of (eta(3)-C(3)H(5))Pd(PPh(3))Cl (1.0 mol %) to give 1-boryl-2-silyl-1-alkenes in high yields. In sharp contrast, selective formation of the inverse regioisomers, 2-boryl-1-silyl-1-alkenes, takes place when the reaction is carried
Tandem Reactions Involving 1-Silyl-3-Boryl-2-Alkenes. New Access to (<i>Z</i>)-1-Fluoro-1-Alkenes, Allyl Fluorides, and Diversely α-Substituted Allylboronates
The reactions of 1-silyl-3-boryl-2-alkenes with various electrophilic reagents (Selecffluor, N-halosuccinimides, benzhydryl, and propargylic alcohols In the presence of a Lewis acid, N-alkoxycarbonyliminium ion) have been investigated as new routes to alpha-substituted allylboronates. Further functional transformations, including allylboration, Suzuki coupling, protodeboronation, and cycloisomerization, have been carried out to illustrate the synthetic potential of these gamma-borylallylsilanes.
Catalytic Enantioselective 1,2-Diboration of 1,3-Dienes: Versatile Reagents for Stereoselective Allylation
作者:Laura T. Kliman、Scott N. Mlynarski、Grace E. Ferris、James P. Morken
DOI:10.1002/anie.201105716
日期:2012.1.9
More with boron: The development of catalyticenantioselective 1,2‐diboration of 1,3‐dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1‐disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized