In Situ Formation of Allyl Ketones via Hiyama−Nozaki Reactions Followed by a Chromium-Mediated Oppenauer Oxidation
作者:Henri S. Schrekker、Martin W. G. de Bolster、Romano V. A. Orru、Ludger A. Wessjohann
DOI:10.1021/jo001750u
日期:2002.4.1
dependent on the substitution pattern of the reaction partners and the reaction conditions. An appropriate choice of these can lead to preferential formation of ketones instead of the alcohols. In addition to its synthetic usefulness, the oxidation-reduction equilibrium is of the utmost importance for the design of enantioselective Hiyama-Nozaki reactions because it is also a potential racemization pathway
Copper-Catalyzed Diamination of Alkenes of Unsaturated Ketohydrazones with Amines
作者:Manman Chen、Li-Jing Wang、Pei-Xing Ren、Xiao-Ying Hou、Zhang Fang、Meng-Nan Han、Wei Li
DOI:10.1021/acs.orglett.7b03401
日期:2018.2.2
A convenient copper-catalyzed intra-/intermoleculardiamination of β,γ-unsaturated hydrazones has been developed with simple amines as external amine sources. The protocol enables efficient access to various nitrogen-containing pyrazolines under mild reaction conditions.
Ruthenium-Catalyzed C−C Bond Forming Transfer Hydrogenation: Carbonyl Allylation from the Alcohol or Aldehyde Oxidation Level Employing Acyclic 1,3-Dienes as Surrogates to Preformed Allyl Metal Reagents
作者:Fumitoshi Shibahara、John F. Bower、Michael J. Krische
DOI:10.1021/ja801213x
日期:2008.5.1
Under the conditions of ruthenium-catalyzedtransferhydrogenation, commercially available acyclic 1,3-dienes, butadiene, isoprene, and 2,3-dimethylbutadiene, couple to benzylic alcohols 1a-6a to furnish products of carbonyl crotylation 1b-6b, carbonyl isoprenylation 1c-6c, and carbonyl reverse 2-methyl prenylation 1d-6d. Under related transferhydrogenation conditions employing isopropanol as terminal
Hydrogen Source Tuned Regiodivergent Asymmetric Hydroalkylations of 2‐Substituted 1,3‐Dienes with Aldehydes by Cobalt‐Catalysis
作者:Xian‐Wang Zeng、Jia‐Ni Lin、Wei Shu
DOI:10.1002/anie.202403073
日期:2024.6.3
Catalytic methods allowing for the reliable prediction and control of diverse regioselectivity along with the control of enantioselectivity to access different regio‐ and enantiomers by switching the least reaction parameters are one of the most attractive ways in organic synthesis, which provide access to diverse enantioenriched architectures from identical starting materials. Herein, a Co‐catalyzed regiodivergent and enantioselective reductive hydroalkylation of 1,3‐dienes with aldehydes have been achieved, furnishing different enantioenriched homoallylic alcohol architectures in good levels of enantioselectivity. The reaction features the switch of regioselectivity tuned by the selection of proton source. The use of an acid as proton source provided asymmetric 1,2‐hydroalkylation products under reductive conditions, yet asymmetric 4,3‐hydroalkylation products were obtained with silane as hydride source. This catalytic protocol allows for the access of homoallylic alcohols with two continuous saturated carbon centers in good levels of regio‐, diastereo‐, and enantioselectivity.