Synthesis of Functionalized [3], [4], [5] and [6]Dendralenes through Palladium‐Catalyzed Cross‐Couplings of Substituted Allenoates

Abstract

Amild method for the synthesis of highly functionalized [3]-[6]dendralenes is reported, representing ag eneral strategy to diversely substituted higher homologues of the dendralenes.T he methodology utilizes allenoates bearing various substitution patterns,a long with aw ide range of boron and alkenyl nucleophiles that couple under palladium catalysis leading to sp-, sp 2 -, and sp 3 -substituted arrays. Regioselective transformations of the newly formed unsymmetrical dendralene derivatives are demonstrated. The use of micellar catalysis,w here water is the global reaction medium, and room temperature reaction conditions,highlights the green nature of this technology. Scheme 4. Regioselective epoxidations of unsymmetrical [3]dendralene 29.Scheme 5. Synthetic route to highly functionalized[ 3]dendralene 37.

Palladium-Catalyzed [2+3] Cycloaddition/Cross-Coupling Reaction: Z/E and Diastereoselective Synthesis of Dendralene-Functionalized Dihydrofurans

“…To date, [3]­dendralenes or cross-conjugated trienes have been used for the rapid construction of chiral polycyclic structures and play an important role in many fields, such as polymer chemistry, synthetic chemistry, natural product chemistry, and functional materials . In recent years, the synthesis of [3]­dendrarenes has developed rapidly …”

[n]Dendralenes as a Platform for Selective Catalysis: Ligand-Controlled Cu-Catalyzed Chemo-, Regio-, and Enantioselective Borylations

“…3h,8 Lipshutz showed that only judiciously designed [3]dendralenic Michael acceptors undergo selective Cu-catalyzed 1,4-or 1,6-conjugate addition (Figure 1B). 9 The development of general catalytic and selective protocols for the functionalization of one specific alkene in minimally biased [n]dendralenes remains elusive.…”