686747-84-2Relevant academic research and scientific papers
A One-Pot Multicomponent Coupling Reaction for the Stereocontrolled Synthesis of (Z)-Trisubstituted Allylic Alcohols
Chen, Young K.,Walsh, Patrick J.
, p. 3702 - 3703 (2004)
In this Communication, we outline a new one-pot, multicomponent coupling reaction that allows easy access to (Z)-trisubstituted allylic alcohols. Our strategy is based on E to Z isomerization of the 1-bromo-1-dialkylvinylborane upon reaction with dialkylzinc reagents, and subsequent transmetalation to give (Z)-trisubstituted vinylzinc species. In situ trapping of the reactive vinylzinc intermediates with aldehydes furnished a series of (Z)-trisubstituted allylic alcohols. This method represents a viable alternative to the Still?Gennari modification of the HWE olefination reaction, and it has the advantage that it allows coupling of larger fragments. Copyright
Synthesis of (-)-hennoxazole A: Integrating batch and flow chemistry methods
Fernández, Amadeo,Levine, Zebulon G.,Baumann, Marcus,Sulzer-Mossé, Sarah,Sparr, Christof,Schl?ger, Sabrina,Metzger, Albrecht,Baxendale, Ian R.,Ley, Steven V.
supporting information, p. 514 - 518 (2013/04/10)
A new total synthesis of (-)-hennoxazole A is reported. The synthetic approach is based on the preparation of three similarly sized fragments resulting in a fast and convergent assembly of the natural product. The three key reactions of the synthesis include a highly stereoselective 1,5-anti aldol coupling, a gold-catalyzed alkoxycyclization reaction, and a stereocontrolled diene cross-metathesis. The synthesis involves integrated batch and flow chemistry methods leading to the natural product in 16 steps longest linear sequence and 2.8% overall yield. Georg Thieme Verlag Stuttgart · New York.
One-pot multicomponent coupling methods for the synthesis of diastereo- and enantioenriched (Z)-trisubstituted allylic alcohols
Kerrigan, Michael H.,Jeon, Sang-Jin,Chen, Young K.,Salvi, Luca,Carroll, Patrick J.,Walsh, Patrick J.
scheme or table, p. 8434 - 8445 (2009/10/23)
(Z)-Trisubstituted allylic alcohols are widespread structural motifs in natural products and biologically active compounds but are difficult to directly prepare. Introduced herein is a general one-pot multicomponent coupling method for the synthesis of (Z)-α,α,β-trisubstituted allylic alcohols. (Z)-Trisubstituted vinylzinc reagents are formed in situ by initial hydroboration of 1-bromo-1-alkynes. Addition of dialkylzinc reagents induces a 1,2-metalate rearrangement that is followed by a boron-to-zinc transmetalation. The resulting vinylzinc reagents addto a variety of prochiral aldehydes to produce racemic (Z)-trisubstitut ed allylic alcohols. When enantioenriched aldehyde substrates are employed, (Z)-trisubstituted allylic alcohols are isolated with high dr (>20:1in many cases). For example, vinylation of enantioenriched benzyl-prote cted α- and β-hydroxy propanal derivatives furnished the expected anti-Felkin addition products via chelation control. Surprisingly, silyl-protected α-hydroxy aldehydes also afford anti-Felkin addition products. A protocol for the catalytic asymmetric addition of (Z)-trisubstituted vinylzinc reagents to prochiral aldehydes with a (-)-MIB-based catalyst has also been developed. Several additives were investigatedas inhibitors of the Lewis acidic alkylzinc halide byproducts, which pr omote the background reaction to form the racemate. R-Ethyl and R-cyclohexyl (Z)-trisubstituted allylic alcohols can now be synthesized with excellent levels of enantioselectivity in the presence of diamine inhibitors.
