traditional C −C cross‐coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the crosscoupling of allylstannanes and activated alkylbromides to form C −C bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solidsupport, which allowed
TRANS-3,5-DISUBSTITUTEDPYRROLIDINE: ORGANOCATALYST FOR anti-MANNICH REACTIONS
申请人:Tanaka Fujie
公开号:US20070117986A1
公开(公告)日:2007-05-24
A compound of Formula I is disclosed, in which R is a substituent containing a hydrogen bond-forming atom within three atoms from the ring carbon to which the substituent is bonded; X is CH
2
, O, S or NR
1
, wherein R
1
is a hydrocarbyl group or an amino-protecting group having one to about 18 carbon atoms; R
2
is hydrido or a hydrocarbyl group containing one to about twelve carbon atoms; and R
3
is hydrido or methyl, but both R
2
and R
3
are not hydrido when X is CH
2
A molecule of Formula I and those in which R
2
and R
3
can both be hydrido (Formula X) functions as a catalyst in a Mannich reaction to asymmetrically form β-aminoaldehyde or β-aminoketone diastereomeric products having two chiral centers on adjacent carbon atoms and in which the anti-diastereomers are in excess over the syn-diastereomers. Methods for carrying out those syntheses are also disclosed.
Direct organocatalytic asymmetric Mannich-type reactions in aqueous media: one-pot Mannich-allylation reactions
作者:Armando Córdova、Carlos F Barbas
DOI:10.1016/s0040-4039(03)00019-4
日期:2003.2
organocatalytic asymmetric Mannich-type reactions in aqueousmedia are demonstrated herein. l-Proline-catalyzed reactions in aqueousmedia to provide β-formyl substituted α-amino acid derivatives with excellent diastereoselectivities (dr up to 19:1, syn/anti) and high enantioselectivities (ee between 72 and >99%). These conditions provided for the development of novel one-potasymmetric syntheses of cyclic
Site-Selective Catalytic Deaminative Alkylation of Unactivated Olefins
作者:Shang-Zheng Sun、Ciro Romano、Ruben Martin
DOI:10.1021/jacs.9b07489
日期:2019.10.16
A catalytic deaminative alkylation of unactivatedolefins is described. The protocol is characterized by its mild conditions, wide scope - including the use of ethylene as substrate -, and exquisite site-selectivity pattern for both a-olefins and internal olefins, thus unlocking a new catalytic platform to forge sp3-sp3 linkages, even in the context of late-stage functionalization.
Precursors for fragrant ketones and fragrant aldehydes
申请人:Givaudan SA
公开号:EP1262473A1
公开(公告)日:2002-12-04
The present invention refers to fragrance precursors of formula I
for a fragrant ketone of formula II
and one or more fragrant aldehydes or ketones of formula III and IV,
These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.