123290-33-5Relevant academic research and scientific papers
Nucleophilic Reactivity of Zinc and Copper Carbenoids. 2
Knochel, Paul,Chou, Tso-Sheng,Chen, Huai Gu,Yeh, Ming Chang P.,Rozema, Michael J.
, p. 5202 - 5204 (1989)
The rectivity of the new zinc and copper carbenoids PivOCH2Cu(CN)ZnI (4) and ICH2Cu*ZnI2 (5) toward various electrophiles has been investigated.Of special interest is the direct and highly stereoselective conversion of allylic bromides to the corresponding homoallylic iodides by using the reagent ICH2Cu*ZnI2
Combined effects on selectivity in Fe-catalyzed methylene oxidation
Chen, Mark S.,White, M. Christina
scheme or table, p. 533 - 571 (2010/10/05)
Methylene C-H bonds are among the most difficult chemical bonds to selectively functionalize because of their abundance in organic structures and inertness to most chemical reagents. Their selective oxidations in biosynthetic pathways underscore the power of such reactions for streamlining the synthesis of molecules with complex oxygenation patterns. We report that an iron catalyst can achieve methylene C-H bond oxidations in diverse natural-product settings with predictable and high chemo-, site-, and even diastereoselectivities. Electronic, steric, and stereoelectronic factors, which individually promote selectivity with this catalyst, are demonstrated to be powerful control elements when operating in combination in complex molecules. This small-molecule catalyst displays site selectivities complementary to those attained through enzymatic catalysis.
Preparation and Reactivity of Highly Functionalized Organometallics at the α Position of Oxygen or Nitrogen
Knochel, Paul,Chou, Tso-Sheng,Jubert, Carole,Rajagopal, Duddu
, p. 588 - 599 (2007/10/02)
α-Halogenoalkyl carboxylates (FG-R1CH(X)(OCOR2); FG = COOR, CN, SR; X = I, Br) were readily prepared by the addition of an acid chloride or bromide (R2COX; X = Br or Cl) to an aldehyde (FG-RCHO) in the presence of a catalytic amount of ZnCl2.They insert efficiently zinc dust in THF-DMSO (X = Br, 8 - 10 deg C, 6 - 10 h) affording the corresponding zinc organometallics at the α position to oxygen FG-RCH(ZnBr)(OAc).After the addition of the THF-soluble copper salt CuCN*2LiCl, the corresponding copper reagents FG-RCH(Cu(CN)ZnBr)(OAc) are formed and reacted with variousclasses of electrophiles such as acid chlorides, aldehydes, enones, allylic and alkynyl halides, activated alkynes, nitro olefins and alkylidenemalonates providing polyfunctional molecules in excellent yields.Similarly, zinc organometallics at the α position to the nitrogen of cyclic imides were prepared by the zinc insertion to cyclic α-chloromethyl (or α-chloroethyl) imides.After their transmetalation to the corresponding copper organometallic ((R1CO)2NCH(R)(Cu(CN)ZnCl); R = Me or H), they were reacted with allylic and alkynyl halides and ethyl propiolate affording polyfunctional imides.The reaction of cyclic N-(chloromethyl)imides with aldehydes in the presence of chromium(II) chloride in THF furnishes protected amino alcohols in 36 - 95percent yield.
