Mikimoto Katsukawa

Bio: Mikimoto Katsukawa is an academic researcher from Nagoya University. The author has contributed to research in topics: Phosphoric acid & Carbocation. The author has an hindex of 5, co-authored 10 publications receiving 254 citations. Previous affiliations of Mikimoto Katsukawa include University of California, Berkeley.

Gold(I)-catalyzed enantioselective synthesis of benzopyrans via rearrangement of allylic oxonium intermediates.

Abstract: The first transition metal catalyzed asymmetric carboalkoxylation reaction of propargyl esters is described. The (R)-MeO-DTBM-BIPHEP(AuCl)2-catalyzed reactions allow for the construction of benzopyrans containing quaternary stereocenters with excellent enantioselectivity. Experimental evidence supports a mechanism proceeding via the generation of a stabilized carbocation from an allylic oxonium intermediate and subsequent trapping by a chiral allylgold(I) spieces.

Selective synthesis of cyclic phosphoric acid diesters through oxorhenium(vii)-catalyzed dehydrative condensation of phosphoric acid with alcohols

Abstract: The selective synthesis of phosphoric acid diesters has been achieved through the direct catalytic dehydrative condensation of phosphoric acid with two equivalents of alcohols. The present method works especially well for the synthesis of cyclic phosphoric acid diesters. The combination of perrhenic acid and N-methylbenzylamine efficiently catalyzes the dehydrative condensation of phosphoric acid with equimolar amounts of diols to give cyclic phosphoric acid diesters in excellent yields.

Gold(I)-Catalyzed Activation of Alkynes for the Construction of Molecular Complexity

Abstract: 1.1. General Reactivity of Alkyne-Gold(I) Complexes For centuries, gold had been considered a precious, purely decorative inert metal. It was not until 1986 that Ito and Hayashi described the first application of gold(I) in homogeneous catalysis.1 More than one decade later, the first examples of gold(I) activation of alkynes were reported by Teles2 and Tanaka,3 revealing the potential of gold(I) in organic synthesis. Now, gold(I) complexes are the most effective catalysts for the electrophilic activation of alkynes under homogeneous conditions, and a broad range of versatile synthetic tools have been developed for the construction of carbon–carbon or carbon–heteroatom bonds. Gold(I) complexes selectively activate π-bonds of alkynes in complex molecular settings,4−10 which has been attributed to relativistic effects.11−13 In general, no other electrophilic late transition metal shows the breadth of synthetic applications of homogeneous gold(I) catalysts, although in occasions less Lewis acidic Pt(II) or Ag(I) complexes can be used as an alternative,9,10,14,15 particularly in the context of the activation of alkenes.16,17 Highly electrophilic Ga(III)18−22 and In(III)23,24 salts can also be used as catalysts, although often higher catalyst loadings are required. In general, the nucleophilic Markovnikov attack to η2-[AuL]+-activated alkynes 1 forms trans-alkenyl-gold complexes 2 as intermediates (Scheme 1).4,5a,9,10,12,25−29 This activation mode also occurs in gold-catalyzed cycloisomerizations of 1,n-enynes and in hydroarylation reactions, in which the alkene or the arene act as the nucleophile. Scheme 1 Anti-Nucleophilic Attack to η2-[AuL]+-Activated Alkynes

Gold-catalyzed carbon-heteroatom bond-forming reactions.

Abstract: A.L.-P. thanks CSIC for a contract under the JAE-doctor program. Financial support by PLE2009 project from MCIINN and Consolider-Ingenio 2010 (proyecto MULTICAT) are also acknowledged.

Gold and platinum catalysis—a convenient tool for generating molecular complexity

Abstract: This critical review intends to familiarize the reader with the essence of π-acid catalysis, in particular with reactions or reaction cascades effected by gold and platinum complexes. Even though materialized in apparently different reactivity modes, such noble metal catalyzed processes can be easily rationalized on the basis of a uniform mechanistic scheme that is outlined in detail. The resulting increase in molecular complexity is illustrated by selected natural product total syntheses and the formation of various intricate non-natural compounds (106 references).

Development of Catalysts and Ligands for Enantioselective Gold Catalysis

Abstract: During the past decade, the use of Au(I) complexes for the catalytic activation of C–C π-bonds has been investigated intensely. Over this time period, the development of homogeneous gold catalysis has been extraordinarily rapid and has yielded a host of mild and selective methods for the formation of carbon–carbon and carbon–heteroatom bonds. The facile formation of new bonds facilitated by gold naturally led to efforts toward rendering these transformations enantioselective.In this Account, we survey the development of catalysts and ligands for enantioselective gold catalysis by our research group as well as related work by others. We also discuss some of our strategies to address the challenges of enantioselective gold(I) catalysis. Early on, our work with enantioselective gold-catalyzed transformations focused on bis(phosphinegold) complexes derived from axially chiral scaffolds. Although these complexes were highly successful in some reactions like cyclopropanation, the careful choice of the weakly co...