1,4-Conjugate addition of the reformatsky reagent to α-nitrostyrenes: A new synthesis of γ-nitroesters.
摘要:
alpha-Nitrostyrenes react with the Reformatsky reagent to yield the corresponding 1,4-addition products. The reaction represents a practical and convenient route to ethyl 3-aryl-4-nitrobutanoates.
of α,β-unsaturated methyl ketone/nitro compounds from benzylic amines through an oxidation–aldol/Henry reaction is reported. The reaction proceeded well by using MCPBA as oxidant and CuCl2·2H2O as catalyst. A variety of functionalized α,β-unsaturated methyl ketone/nitro compounds were assembled in moderate yields by application of this catalytic one-pot reaction.
Preparation of Pyrrolidine-Based PDE4 Inhibitors via Enantioselective Conjugate Addition of α-Substituted Malonates to Aromatic Nitroalkenes
作者:Paul J. Nichols、John A. DeMattei、Bradley R. Barnett、Nicole A. LeFur、Tsung-Hsun Chuang、Anthony D. Piscopio、Kevin Koch
DOI:10.1021/ol060398p
日期:2006.3.1
[reaction: see text] The enantioselective conjugateaddition of alpha-substituted malonates to aromatic nitroalkenes generates a stereocenter at the carbon bearing the aromatic group and an adjacent prochiral center from the alpha-substituted malonate. Nitro reduction followed by diastereoselective cyclization provides pyrrolidinones with two contiguous stereocenters, one of which is quaternary. This
The present invention provides an organocatalyst of formula (I),
wherein R
1
is —H, —OH, —O—Si(R
4
)(R
5
)(R
6
) or C
1-6
alkoxy, in which R
4
, R
5
and R
6
are identical or different and independently selected from the group consisting of C
1-6
alkyl, phenyl and phenyl substituted with C
1-6
alkyl; R
2
is —OH or ═O; X
1
is one selected from the group consisting of —NH—, —S— and
X
2
is one selected from the group consisting of —C(═O)—, —CH
2
— and
and X
1
is different from X
2
. The high yield and enantioselectivity of an addition reaction are obtained by using the organocatalyst of the present invention.
The asymmetric challenge! New camphor‐based prolinamides were designed, synthesized, and proven to be a highly efficient organocatalysts for asymmetricMichael reactions. Treatment of unmodified aldehydes with nitroalkenes in the presence of 5–10 mol % organocatalysts provided the desired Michael products in high chemical yields (up to 94 %) and high to excellent levels of diastereo‐ and enantioselectivities
Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate–thiourea hybrid with mechanistic DFT analysis
作者:Chandra S. Azad、Imran A. Khan、Anudeep K. Narula
DOI:10.1039/c6ob02158a
日期:——
core scaffold were synthesized and examined as catalysts for the asymmetricMichael addition reaction of aryl/alkyl trans-β-nitrostyrenes over cyclohexanone and other Michael donors having active methylene. Excellent enantioselectivities (<95%), diastereoselectivities (<99%), and yields (<99%) were attained undersolvent free conditions using 10 mol% of 1d0. The obtained results were explained through