A palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate. A facile approach to optically active dihydrocoumarins
作者:Jingfu Li、Wenju Chang、Wenlong Ren、Wei Liu、Haining Wang、Yian Shi
DOI:10.1039/c5ob01431j
日期:——
An effective palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate as a CO source is described.
Chiral [2.2.2] Dienes as Ligands for Rh(I) in Conjugate Additions of Boronic Acids to a Wide Range of Acceptors
作者:Christian Defieber、Jean-François Paquin、Sonia Serna、Erick M. Carreira
DOI:10.1021/ol048240x
日期:2004.10.1
[reaction: see text] We document a series of investigations that led to new substituted [2.2.2]-diene ligands which display high selectivity in Rh(I)-catalyzed conjugate addition reactions to substrates not previously examined with diene ligands. Moreover, we disclose an unexpected, interesting effect that results from the introduction of a third C=C onto the ligand scaffold (cf. 1).
We previously reported the synthesis of BICMAP (1a) via 6-diphenylphosphino-2,3-dihydrobenzofuran as a key intermediate. However, we did not successfully synthesize BICMAP analogues via a similar synthetic route. Herein we report the second-generation synthesis of BICMAP and its derivatives via diethylphosphonate as a key intermediate.
An efficient asymmetric hydroesterfication of diarylmethyl carbinols is developed for the first time with a Pd‐WingPhos catalyst, resulting in a series of chiral 4‐aryl‐3,4‐dihydrocoumarins in excellent enantioselectivities and good yields. The method features mild reaction conditions, a broad substrate scope, use of easily accessible starting materials, and low palladium loadings. A plausible stereochemical
Copper‐Catalyzed Asymmetric 1,4‐Hydroboration of Coumarins with Pinacolborane: Asymmetric Synthesis of Dihydrocoumarins
作者:Hyohyun Kim、Jaesook Yun
DOI:10.1002/adsc.201000310
日期:2010.10.9
An efficient asymmetric addition of pinacolborane to 4-substituted coumarins proceeded with high enantioselectivity in the presence of a copper(I)-QuinoxP complex as a catalyst to produce the corresponding 1,4-hydroboration products. Treatment of the intermediates with electrophiles, without isolation, resulted in enantioenriched dihydrocoumarins. The utility of this protocol was demonstrated in the