Synthesis of β,β-Disubstituted Vinyl Boronates via the Ruthenium-Catalyzed Alder Ene Reaction of Borylated Alkynes and Alkenes
作者:Eric C. Hansen、Daesung Lee
DOI:10.1021/ja0424629
日期:2005.3.1
Ruthenium-catalyzed Alderenereactions between borylated alkynes and terminal alkenes give the corresponding β,β-disubstituted vinyl boronates with high selectivity for the branched isomer. The stereochemistry of the vinyl boronate moiety was the result of a formal trans addition of the ene subunit across the alkyne, which is the opposite stereochemical outcome observed for other internal alkynes
Regiochemical Control in the Metal-Catalyzed Transposition of Allylic Silyl Ethers
作者:Eric C. Hansen、Daesung Lee
DOI:10.1021/ja0620639
日期:2006.6.1
A novel mode of regiochemical control over the allylic [1,3]-transposition of silyloxy groups catalyzed by Re2O7 has been developed. This strategy relies on a cis-oriented vinyl boronate, generated from the Alder-ene reaction of homoallylic silyl ethers and alkynyl boronates, to trap out the allylic hydroxyl group. The resulting cyclic boronic acids are excellent partners for cross-coupling reactions
Stereocontrolled synthesis of 2-alkenyl-4-methylene tetrahydropyrans
作者:Eric C. Hansen、Daesung Lee
DOI:10.1016/j.tetlet.2004.07.063
日期:2004.9
A variety of 2-alkenyl-4-methylene tetrahydropyrans were synthesized via consecutive transition metal-catalyzed bond forming processes. In this approach, ruthenium-catalyzed coupling of homoallylic carbonates and homopropargylic alcohols generates substrates containing the requisite functionality for a palladium-mediated cyclization, thereby providing concise access to the target structures. The installation