Selective Construction of C−C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
作者:Xin Liu、Thomas Werner
DOI:10.1002/adsc.202001209
日期:2021.2.16
manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon‐carbon single (C−C) and carbon‐carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C−C vs. C=C bonds can be controlled by the
An umpolung-enabled copper-catalysed regioselective hydroamination approach to α-amino acids
作者:Soshi Nishino、Masahiro Miura、Koji Hirano
DOI:10.1039/d1sc03692k
日期:——
hydroxylamine as an umpolung, electrophilicamination reagent. Additionally, a judicious choice of conditions involving the CsOPiv base and DTBM-dppbz ligand of remote steric hindrance enables the otherwise challenging C–N bond formation at the α position to the carbonyl. The point chirality at the β-position is successfully controlled by the Xyl-BINAP or DTBM-SEGPHOS chiral ligand with similarly remote
Conjugate Boration of β,β-Disubstituted Unsaturated Esters: Asymmetric Synthesis of Functionalized Chiral Tertiary Organoboronic Esters
作者:Xinhui Feng、Jaesook Yun
DOI:10.1002/chem.201002361
日期:2010.12.10
Challenging tertiaryorganoboronicesters containing a β‐ester group were prepared enantioselectively via the asymmetricconjugateboration of β,β‐disubstituted α,β‐unsaturatedesters with a copper–phosphine catalyst (see scheme). The functionalized organoboron derivatives can be utilized as a carbon nucleophile to form all‐carbon quaternary centers.
Catalytic Enantioselective Construction of β-Quaternary Carbons via a Conjugate Addition of Cyanide to β,β-Disubstituted α,β-Unsaturated Carbonyl Compounds
作者:Yuta Tanaka、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/ja1035286
日期:2010.7.7
The first general catalyticenantioselectiveconjugate addition of cyanide to beta,beta-disubstituted alpha,beta-unsaturated ketones and N-acylpyrroles was developed using a strontium catalyst derived from Sr(O(i)Pr)(2) and new chiral ligand 5. The reaction exhibited excellent enantioselectivity and a wide substrate scope using 0.5-10 mol % catalyst. 1,4-Adducts containing beta-quaternary carbons were
A visible-light-driven and room temperature photo-Wolff-Kischner reaction of sulfur ylides and N-tosylhydrazones has been developed for the first time to provide modular access to alkene synthesis. The high functional group tolerance and broad substrate scope were demonstrated by more than 60 examples. Both E- and Z-olefinic stereochemistry in the products could be controlled with excellent stereoselectivity