Palladium‐Catalyzed Enantioselective Alkoxycarbonylation of Propargylic Carbonates with (R)‐ or (S)‐3,4,5‐(MeO)₃‐MeOBIPHEP

Abstract

(R)- and (S)-3,4,5-(MeO) -MeOBIPHEP have been identified as the efficient chiral ligands for the palladium-catalyzed highly enantioselective synthesis of 2,3-allenoates from different types of easily available racemic propargylic carbonates with 90-98 % ee and decent yields. The potential of the products was demonstrated with high chirality transfer efficiency.

Catalytic Regio- and Enantioselective Proton Migration from Skipped Enynes to Allenes

“…[44][45][46][47][48][49][50][51][52] Catalytic enantioselective synthesis of axially chiral allenes from prochiral or racemic starting materials is a current topic of interest. [21][22][23][24][25] Representative methods in this category include (1) addition reactions to conjugated enynes or diynes, [53][54][55][56][57][58][59][60][61][62][63] (2) allylic substitution reactions or [3 + 2] cycloadditions through alkylidene p-allylpalladium intermediates, [64][65][66][67][68][69][70][71][72][73][74][75] (3) palladium-catalyzed allylic b-hydride elimination of internal enol triflates, 76 (4) nickel-catalyzed propargyl Claisen rearrangement, 77 (5) deprotonative C(sp 2 )-H functionalization of racemic allenes, [78][79][80][81] (6) alkynylogous Mukaiyama aldol reaction,…”

Nickel-catalyzed switchable 1,3-dienylation and enantioselective allenylation of phosphine oxides

“…Enantioselective couplings of propargylic alcohol derivatives with various nucleophiles have been reported to afford chiral allenes (Fig. 1A) [45][46][47][48][49][50] . Despite extensive efforts, there is no extant catalytic protocol for constructing enantiomerically enriched allenylphosphoryl derivatives from two readily available fragments.…”