Multiphase HomogeneousCatalysis

Edited by B. Cornils,W. A. Herrmann,I. T. Horv�th, W.Leitner, S. Mecking,H. Olivier-Bourbi-gou and D. Vogt.Wiley-VCH, Wein-heim 2005. 871 pp.,2 Vols., hardcoverE 329.00.—ISBN3-527-30721-4

This book summarizes the researchcarried out during the last two decadesin the area of multiphase homogeneouscatalysis, and describes the latest devel-opments. It does not set out to cover thephysical chemistry of the processesinvolved (mass-transport phenomena,distribution equilibria, etc.), nor is itprimarily concerned with the (impor-tant) question of which phase or inter-facial layer is the site of action inindividual catalytic reactions. Instead,the aim is to describe the methods thathave been used to study the processes,and to report on the present state ofknowledge coming from the research,illustrated by examples.

This kind of review is unusual, andthere is no other comparable book inthis field. The range of topics coveredincludes not only organic and aqueousmultiphase catalysis but also processesthat use fluorous phases, ionic liquids, orsupercritical carbon dioxide. The use ofsoluble polymers for the immobilizationof catalysts is also discussed, as also aremembrane techniques for the separationof catalysts from products, and the use ofmetal-modified dendrimers as precata-lysts. The survey is rounded off by a

description of the catalytic applicationsof various types of micromicellar sys-tems.

Staying within with the basic conceptof multiphase catalysis, the book alsodiscusses systems in which the phasebehavior is temperature-dependent.However, these discussions are scat-tered throughout the whole work, andconsequently the reader has to spend alittle more time to get an overview ofthis topic. Phase-transfer catalysis isonly mentioned as a marginal topic.On the other hand, the currently veryactive topic of process simplification byheterogenization, which has developedout of multiphase catalysis, is treated indetail. Carrier-fixed systems such asSAPC and SILP can be regarded asinterfacial catalysts, and there is a trendtowards increasing use of these systems,which not only give simpler processesbut also offer possibilities for workingwith very small quantities of reactionmedia such as ionic liquids (SILP).

It is pleasing that the authors haverecognized the importance of includingtypical data on parameters that arerelevant to working with multiphasesystems. They have also included usefuldescriptions of industrial multiphaseprocesses, such as the SHOP process,the Ruhrchemie–Rh*ne-Poulenc pro-cess, aqueous multiphase hydrogena-tion, the Kuraray butadiene telomeriza-tion process, and the BASIL processusing ionic liquids. The first use ofsupercritical carbon dioxide in an indus-trial catalytic process—the Swan processfor heterogeneously catalyzed hydroge-nation of isophores—is also described.As the technology for multiphase cata-lytic processes using supercritical fluidshas now become available on an indus-trial scale, one can expect that suchprocesses will be adopted increasingly inthe future.

The various approaches to usingcatalytic processes in multiphase sys-tems or at interfaces are illustrated bymany detailed examples, so that thebook also provides a good survey of therelevant current literature. Readers whoare interested in finding out aboutrecent developments in the field ofhomogeneous catalysis will find awealth of information here. In view ofthe unique underlying concept of thebook Multiphase Homogeneous Cataly-

sis, and the high quality of the descrip-tions, it can be strongly recommendedfor everyone interested in the subject.

Olaf WalterForschungszentrum Karlsruhe (Germany)

Boronic Acids

Preparation, Appli-cations in OrganicSynthesis andMedicine. Edited byDennis G. Hall.Wiley-VCH, Wein-heim 2005. 545 pp.,hardcoverE 149.00.—ISBN3-527-30991-8

The chemistry of boronic acids and theirderivatives has seen a huge increase ininterest in the past twenty years. Thiscan be traced largely to the develop-ment by Suzuki of the eponymouspalladium-catalyzed cross-couplingreaction of boronic acids with organichalides, a reaction which has become aworkhorse in the pharmaceutical, agro-chemical and fine chemical industries onboth a discovery-chemistry and manu-facturing scale. This has led to improve-ments in methods for the preparation ofboronic acids and hence their growingcommercial availability. Boronic acidderivatives have a number of attractiveproperties, such as stability, ease ofhandling, air and moisture tolerance,and a lack of intrinsic toxicity, which hasencouraged chemists to extend therange of reactions undertaken by thesespecies. One of the main younger practi-tioners in this field, Dennis Hall fromthe University of Alberta, has assem-bled a high quality author list to sum-marize recent developments in the field.

The book opens with a contributionfrom Hall himself on the structure,properties and synthesis of boronicacid derivatives, together with a briefdiscussion of their general modes ofreactivity. The collation of structuraland spectroscopic information is partic-

AngewandteChemieBooks

2005Angew. Chem. Int. Ed. 2006, 45, 2005 – 2006 6 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ularly useful to those new to the field.The subsequent chapter looks in moredetail at transition-metal catalyzed bor-ylation reactions for the synthesis of(particularly) aryl and heteroaryl boro-nate derivatives. This is a burgeoningarea and this comparative review istimely, balanced, and well written. Rad-ical and cycloaddition reactions tounsaturated boronic acids also allowaccess to valuable modified boronatederivatives and are reviewed compre-hensively later in the book.

Boronic acid derivatives are mostwidely used as latent organic nucleo-philes, activated either by the additionof Lewis base alone or by transmetala-tion to metals such as palladium, rho-dium, copper, or zinc. Unsurprisingly,the bulk of the chemistry in the booktherefore focuses on these areas. Con-tributions include discussions of palla-dium-catalyzed cross-couplings, rho-dium-catalyzed additions to carbonelectrophiles, copper-mediatedC-heteroatom bond formation, anduncatalyzed additions to imines/imini-ums and carbonyl compounds. These areall largely timely reviews. The chapteron C-heteroatom bond formation byChan and Lam features a useful criticalcomparison with competing palladium-catalyzed protocols. The rhodium-cata-lyzed addition of boronic acids to carbonelectrophiles has been one of the successstories of recent years. Aside from thepractical convenience of the experimen-tal conditions by comparison with stan-dard organometallic reactions, the abil-ity to tune reactivity by ligand modifi-cation (including asymmetric variants)is a hugely attractive feature and is wellillustrated here. The chapter on theSuzuki reaction itself is perhaps one of

the least valuable contributions to thebook, since the reaction has been soextensively reviewed elsewhere. Thechapter focuses on selected recent appli-cations which illustrate the breadth ofapplication of the reaction, from targetsynthesis to materials science. While thisis an entertaining interlude, anyone stillunfamiliar with this reaction is perhapsbetter directed to the existing morecomprehensive reviews which Suzukihimself cites in his introduction.

The other dominant chemistry ofboronic acids is their Lewis acidity, andmost of the remaining chemical chaptersof the book focus on this aspect. The useof boronate derivatives as templates forasymmetric carbenoid homologationreactions has long been a powerfulmethod and the man most responsiblefor the growth of this field, DonaldMatteson, contributes an excellent per-spective, crowned by its application inthe synthesis of the first licensed boronicacid containing pharmaceutical: Millen-nium5s proteasome inhibitor bortezo-mib (Velcade).

The use of boronic acids and borinicacids in Brønsted and Lewis acid catal-ysis is reviewed, with particular empha-sis on the use of boron as a template forthe assembly of chiral Lewis acid cata-lysts. Oxazaborolidines are not onlyLewis acidic but also Lewis basic(through the nitrogen atom) and thisforms the basis of the most widely usedmethod for the laboratory scale asym-metric reduction of ketones, the Corey-Bakshi-Shibata reaction. This area hasbeen reviewed numerous times, not leastby Corey himself, but Cho5s chapterprovides a worthwhile update, focusingon the use of the catalyst in the reduc-tion of polyfunctional molecules and

applications in the reduction of non-ketone substrates.

The Lewis acidic properties of bor-onates also form the basis for theirefficient complexation of sugar mole-cules, a fact which has been widelyexploited in the development of selec-tive carbohydrate sensors. Tony James5chapter guides the novice through theunderlying principles behind the proc-esses, then takes a critical view of thepros and cons of the various systemsdeveloped to date. Finally, the use ofboronic acids and derivatives in medic-inal chemistry applications, both aspharmacophores for enzyme inhibitionand in boron neutron capture therapy isdiscussed.

Overall, Hall5s book provides anexcellent starting point from which toexplore the chemistry of boronic acids,but also one which gives a perspectiveon likely future developments. A clearpositive feedback loop emerges fromthe material herein, whereby the take-up of new reactions and applicationsleads to demands for improved methodsfor the preparation of boronate sub-strates which in turn offers wider scopefor further new reactivity patterns to beexploited. Hall states at the outset thathis task was to provide the first compre-hensive book on the chemistry andbiology of boronic acids; this he hasdone, but at the pace of current devel-opments, a second edition might not beso long in arriving.

Steve MarsdenDept. of ChemistryUniversity of Leeds

DOI: 10.1002/anie.200585331

Books

2006 www.angewandte.org 6 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. Int. Ed. 2006, 45, 2005 – 2006