930608-33-6Relevant academic research and scientific papers
Iterative approach to polyketide-type structures: Stereoselective synthesis of 1,3-polyols utilizing the catalytic asymmetric Overman esterification
Binder, Joerg T.,Kirsch, Stefan F.
, p. 4164 - 4166 (2007)
An iterative systematic approach to the 1,3-polyol motif has been developed to provide access to all possible stereoisomers by utilizing the catalytic asymmetric Overman esterification for the construction of all stereogenic centres. The Royal Society of
Palladacyclic imidazoline-naphthalene complexes: Synthesis and catalytic performance in Pd(II)-catalyzed enantioselective reactions of allylic trichloroacetimidates
Cannon, Jeffrey S.,Frederich, James H.,Overman, Larry E.
supporting information; body text, p. 1939 - 1951 (2012/04/23)
A new family of air- and moisture-stable enantiopure C,N-palladacycles (PIN-acac complexes) were prepared in good overall yield in three steps from 2-iodo-1-naphthoic acid and enantiopure β-amino alcohols. Three of these PIN complexes were characterized by single-crystal X-ray analysis. As anticipated, the naphthalene and imidazoline rings of PIN-acac complexes 18a and 18b were canted significantly from planarity and projected the imidazoline substituents R1 and R2 on opposite faces of the palladium square plane. Fifteen PIN complexes were evaluated as catalysts for the rearrangement of prochiral (E)-allylic trichloroacetimidate 19 (eq 2) and the SN2′ allylic substitution of acetic acid with prochiral (Z)-allylic trichloroacetimidate 23. Although these complexes were kinetically poor catalysts for the Overman rearrangement, they were good catalysts for the allylic substitution reaction, providing branched allylic esters in high yield. However, enantioselectivities were low to moderate and significantly less than that realized with palladacyclic complexes of the COP family. Computational studies support an anti-acetoxypalladation/syn-deoxypalladation mechanism analogous to that observed with COP catalysts. The computational study further suggests that optimizing steric influence in the vicinity of the carbon ligand of a chiral C,N-palladacycle, rather than near the nitrogen heterocycle, is the direction to pursue in future development of improved enantioselective catalysts of this motif.
Catalytic asymmetric synthesis of chiral allylic esters
Cannon, Jeffrey S.,Kirsch, Stefan F.,Overman, Larry E.
supporting information; experimental part, p. 15185 - 15191 (2010/12/25)
A broadly useful catalytic enantioselective synthesis of branched allylic esters from prochiral (Z)-2-alkene-1-ols has been developed. The starting allylic alcohol is converted to its trichloroacetimidate intermediate by reaction with trichloroacetonitrile, either in situ or in a separate step, and this intermediate undergoes clean enantioselective SN2′ substitution with a variety of carboxylic acids in the presence of the palladium(II) catalyst (Rp,S)-di-μ-acetatobis[(η5- 2-(2′-(4′-methylethyl)oxazolinyl)cyclopentadienyl-1-C,3′-N) (η4-tetraphenylcyclobutadiene)cobalt]dipalladium, (R p,S)-[COP-OAc]2, or its enantiomer. The scope and limitations of this useful catalytic asymmetric allylic esterification are defined.
Catalytic asymmetric synthesis of allylic aryl ethers
Kirsch, Stefan F.,Overman, Larry E.,White, Nicole S.
, p. 911 - 913 (2007/10/03)
(Chemical Equation Presented) The reaction of trichloroacetimidate derivatives of (Z)-2-alken-1-ols with phenol nucleophiles in the presence of the palladium(II) catalyst [COP-OAc]2 provides 3-aryloxy-1-alkenes in high yields and high enantiomeric purity (typically 63-90% yield and 90-97% ee). The reaction is exemplified by 20 examples. The method employs 1 mol % of the commercially available catalysts (S)- or (R)-[COPOAc]2, produces the branched isomer with unprecedented regioselectivity, and is compatible with the presence of base-labile functionality in either reactant.
