Asymmetric Conjugate Addition of Alkylzirconocenes to Cyclopent-4-ene-1,3-dione Monoacetals
作者:Stephen Fletcher、Emeline Rideau、Florian Mäsing
DOI:10.1055/s-0034-1379928
日期:——
Copper-catalyzed asymmetric conjugate additions are powerful reactions that allow the formation of single-enantiomer building blocks in a few steps. However, highly enantioselective conjugate addition to five-membered-ring substrates is more challenging and is often neglected. Here, we report catalytic asymmetric 1,4-addition of alkylzirconocenes, formed in situ from readily available alkenes, to cyclopent-4-ene-1,3-dione monoacetals. Good to high enantioselectivities are observed and the procedure tolerates various functional groups.
Catalytic Enantioselective Synthesis of Prostaglandin E<sub>1</sub> Methyl Ester Using a Tandem 1,4-Addition-Aldol Reaction to a Cyclopenten-3,5-dione Monoacetal
作者:Leggy A. Arnold、Robert Naasz、Adriaan J. Minnaard、Ben L. Feringa
DOI:10.1021/ja015900+
日期:2001.6.1
Conjugate addition reactions are among the most important carbon-carbon bond formation reactions in organic synthesis, and considerable progress has been made in the development of asymmetric Michael additions and 1,4-additions of organometallic reagents. Recently, highly enantioselective copper-catalyzed conjugate addition reactions of diorganozinc reagents to enones have been reported. Among the
Catalytic Enantioselective Synthesis of (−)-Prostaglandin E<sub>1</sub> Methyl Ester Based on a Tandem 1,4-Addition−Aldol Reaction
作者:Leggy A. Arnold、Robert Naasz、Adriaan J. Minnaard、Ben L. Feringa
DOI:10.1021/jo025987x
日期:2002.10.1
catalyst result in highly functionalized cyclopentane building blocks with ee's up to 97%. A new synthesis of cyclopentene-3,5-dione monoacetals is presented as well as its use in a tandem 1,4-addition-aldol protocol for the catalytic asymmetric total synthesis of (-)-PGE(1) methyl ester. This synthesis represents a new approach to this class of natural products. By using only 3 mol % of an enantiomerically