Scope of the nickel catalyzed asymmetric reductive ring opening reaction. Synthesis of enantiomerically enriched cyclohexenols
作者:Mark Lautens、Tomislav Rovis
DOI:10.1016/s0040-4020(97)10211-3
日期:1998.2
Subjecting a variety of oxabicyclo[2.2.1]heptenes to diisobutylaluminum hydride (DIBAL-H) in the presence of a catalytic amount of Ni(COD)2 and (R)-BINAP results in a highly enantioselective ring opening to generate cyclohexenols with ee's typically greater than 90%. The scope of this reaction has been delineated and alternative nickel catalysts have been examined which are less sensitive than Ni(COD)2
Regio- and Stereoselective Reductive Coupling of Bicyclic Alkenes with Propiolates Catalyzed by Nickel Complexes: A Novel Route to Functionalized 1,2-Dihydroarenes and -Lactones
作者:Dinesh Kumar Rayabarapu、Chien-Hong Cheng
DOI:10.1002/chem.200204506
日期:2003.7.7
5 a and b in 81 and 84% yield, respectively. In contrast to the results of 4 with 2, the reaction of dimethyl 7-oxabicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylate (6) with propiolates 2a-d afforded the corresponding reductive coupling/cyclization products, bicyclo[3.2.1]γ-lactones 7a-d in good yields. The reaction provides a convenient one-pot synthesis of γ-lactones with remarkably high regio- and stereoselectivity
ring-opening reactions of 7-heteroatom norbornadienes and norbornenes with various organic halides to give products with multiple stereocenters are described. Treatment of 7-oxabenzonorbornadiene (1a) and 7-carbomethoxy-7-azabenzonorbornadiene (1b) with aryl iodides (ArI) in the presence of NiCl(2)(PPh(3))(2) and Zn powder gave the corresponding ring-opening addition products cis-1,2-dihydro-2-aryl-1-naphthol
CpRuCl(PPh<sub>3</sub>)<sub>2</sub>-Catalyzed Cyclopropanation of Bicyclic Alkenes with Tertiary Propargylic Acetates
作者:Alphonse Tenaglia、Sylvain Marc
DOI:10.1021/jo060276a
日期:2006.4.1
The electron-rich cyclopentadienylruthenium complex CpRuCl(PPh3)2 turns out to be an efficient catalyst for the regio- and stereoselective cyclopropanation of bicyclic alkenes with tertiary propargylic carboxylates. The reaction provides 1,2,3-trisubstituted cyclopropanes in high yields as a single stereoisomer instead of the expected cyclobutenes via [2 + 2] cycloaddition. Functional groups such as
Enantioselective Ring Opening of Aza and Oxabicyclic Alkenes with Dimethylzinc
作者:Mark Lautens、Sheldon Hiebert、Jean-Luc Renaud
DOI:10.1021/ol006052a
日期:2000.6.1
A system for efficient, asymmetric alkylative ringopening of azabenzonorbornadienes and [2.2.1] and [3.2.1] oxabicyclicalkenes was developed. The use of Pd(CH(3)CN)(2)Cl(2) and chiral phosphinooxazoline ligands gives the dihydronaphthalenes, cyclohexenols, and cycloheptenols in excellent yields and enantiomeric excesses.