6957-08-0Relevant articles and documents
Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: Development of an asymmetric aza-pinacol cyclization
Rono, Lydia J.,Yayla, Hatice G.,Wang, David Y.,Armstrong, Michael F.,Knowles, Robert R.
supporting information, p. 17735 - 17738 (2014/01/06)
The first highly enantioselective catalytic protocol for the reductive coupling of ketones and hydrazones is reported. These reactions proceed through neutral ketyl radical intermediates generated via a concerted proton-coupled electron transfer (PCET) event jointly mediated by a chiral phosphoric acid catalyst and the photoredox catalyst Ir(ppy)2(dtbpy)PF6. Remarkably, these neutral ketyl radicals appear to remain H-bonded to the chiral conjugate base of the Bronsted acid during the course of a subsequent C-C bond-forming step, furnishing syn 1,2-amino alcohol derivatives with excellent levels of diastereo- and enantioselectivity. This work provides the first demonstration of the feasibility and potential benefits of concerted PCET activation in asymmetric catalysis.
Ni-catalysed, domino synthesis of tertiary alcohols from secondary alcohols
Berini, Christophe,Navarro, Oscar
, p. 1538 - 1540 (2012/02/16)
The use of in situ generated (NHC)-Ni catalytic species (NHC = N-heterocyclic carbene) allows for the synthesis, in short reaction times, of a variety of tertiary alcohols from secondary alcohols through a domino oxidation-addition protocol.
Organocalcium Chemistry: Preparation and Reactions of Highly Reactive Calcium
Wu, Tse-Chong,Xiong, Heping,Rieke, R. D.
, p. 5045 - 5051 (2007/10/02)
A highly reactive form of calcium was prepared by the reduction of Ca(II) salts with preformed lithium biphenylide.Remarkably, this activated calcium undergoes oxidative addition to organic bromides, chlorides, or even fluorides to form the organocalcium reagents under very mild conditions in high yields.The resulting organocalcium compounds undergo Grignard-type reactions.Transmetalation with Cu(I) salts forms calcium cuprate reagents which undergo a variety of cross-coupling reactions.The activated calcium reacts with 1,3-dienes to yield the corresponding 2-butene-1,4-diylcalcium complexes.These bis-organocalcium reagents can undergo dialkylation reactions with α,ω-alkylene dihalides and dichlorosilanes to form the corresponding 3-, 5-, and 6-membered ring derivatives.Significantly, these reactions are highly stereospecific and regioselective.
