1
|
Meyer CC, Ortiz E, Krische MJ. Catalytic Reductive Aldol and Mannich Reactions of Enone, Acrylate, and Vinyl Heteroaromatic Pronucleophiles. Chem Rev 2020; 120:3721-3748. [PMID: 32191438 PMCID: PMC7904107 DOI: 10.1021/acs.chemrev.0c00053] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Catalytic reductive coupling of enone, acrylate, or vinyl heteroaromatic pronucleophiles with carbonyl or imine partners offers an alternative to base-mediated enolization in aldol- and Mannich-type reactions. In this review, direct catalytic reductive aldol and Mannich reactions are exhaustively catalogued on the basis of metal or organocatalyst. Stepwise processes involving enone conjugate reduction to form discrete enol or (metallo)enolate derivatives followed by introduction of carbonyl or imine electrophiles and aldol reactions initiated via enone conjugate addition are not covered.
Collapse
Affiliation(s)
- Cole C. Meyer
- University of Texas at Austin, Department of Chemistry, Welch Hall
(A5300), 105 E 24 St., Austin, TX 78712, USA
| | - Eliezer Ortiz
- University of Texas at Austin, Department of Chemistry, Welch Hall
(A5300), 105 E 24 St., Austin, TX 78712, USA
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry, Welch Hall
(A5300), 105 E 24 St., Austin, TX 78712, USA
| |
Collapse
|
2
|
Trost BM, Hung C(J, Mata G. Zweikernige Metall‐ProPhenol‐Katalysatoren: Entwicklung und Anwendungen in der Synthese. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201909692] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Barry M. Trost
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| | - Chao‐I (Joey) Hung
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| | - Guillaume Mata
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| |
Collapse
|
3
|
Trost BM, Hung C(J, Mata G. Dinuclear Metal‐ProPhenol Catalysts: Development and Synthetic Applications. Angew Chem Int Ed Engl 2019; 59:4240-4261. [DOI: 10.1002/anie.201909692] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Barry M. Trost
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| | - Chao‐I (Joey) Hung
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| | - Guillaume Mata
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305 USA
| |
Collapse
|
4
|
Trost BM, Hung CIJ, Gnanamani E. Tuning the Reactivity of Ketones through Unsaturation: Construction of Cyclic and Acyclic Quaternary Stereocenters via Zn-ProPhenol Catalyzed Mannich Reactions. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04685] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Chao-I Joey Hung
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Elumalai Gnanamani
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| |
Collapse
|
5
|
Satpathi B, Dutta L, Ramasastry SSV. Metal- and Hydride-Free Pentannulative Reductive Aldol Reaction. Org Lett 2019; 21:170-174. [PMID: 30543435 DOI: 10.1021/acs.orglett.8b03658] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Traditionally, the reductive aldol reaction is a metal-catalyzed and hydride-promoted coupling between enones and aldehydes. We present a phosphine-mediated diastereoselective intramolecular reductive aldol reaction of α-substituted dienones and aldehydes, which is metal-free and hydride-free. The synthetic utility of the reductive aldol adducts is demonstrated by elaborating them in one step to indeno[1,2- b]furanones, indeno[1,2- b]pyrans, and dibenzo[ a, h]azulen-8-ones.
Collapse
Affiliation(s)
- Bishnupada Satpathi
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector 81 , Manauli PO, S. A. S. Nagar, Punjab 140306 , India
| | - Lona Dutta
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector 81 , Manauli PO, S. A. S. Nagar, Punjab 140306 , India
| | - S S V Ramasastry
- Organic Synthesis and Catalysis Lab, Department of Chemical Sciences , Indian Institute of Science Education and Research (IISER) Mohali , Sector 81 , Manauli PO, S. A. S. Nagar, Punjab 140306 , India
| |
Collapse
|
6
|
Abstract
The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon-carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita-Baylis-Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material-nucleophiles, dinucleophiles, electrophiles, and electrophile-nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon-carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon-carbon multiple bond-containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide-generating reactions.
Collapse
Affiliation(s)
- Hongchao Guo
- Department of Applied Chemistry, China Agricultural University, Beijing 100193, P. R. China
| | - Yi Chiao Fan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569, USA
| | - Zhanhu Sun
- Department of Applied Chemistry, China Agricultural University, Beijing 100193, P. R. China
| | - Yang Wu
- Department of Applied Chemistry, China Agricultural University, Beijing 100193, P. R. China
| | - Ohyun Kwon
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569, USA
| |
Collapse
|
7
|
Choo KL, Lautens M. Rhodium-Catalyzed Asymmetric Conjugate Alkynylation/Aldol Cyclization Cascade for the Formation of α-Propargyl-β-hydroxyketones. Org Lett 2018; 20:1380-1383. [DOI: 10.1021/acs.orglett.8b00153] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ken-Loon Choo
- Davenport Research Laboratories,
Department
of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Mark Lautens
- Davenport Research Laboratories,
Department
of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| |
Collapse
|
8
|
Trost BM, Hung CI(J. Broad Spectrum Enolate Equivalent for Catalytic Chemo-, Diastereo-, and Enantioselective Addition to N-Boc Imines. J Am Chem Soc 2015; 137:15940-6. [PMID: 26630114 PMCID: PMC4866649 DOI: 10.1021/jacs.5b11248] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alkynyl ketones are attractive but challenging nucleophiles in enolate chemistry. Their susceptibility to other reactions such as Michael additions and the difficulty of controlling the enolate geometry make them difficult substrates. Mannich-type reactions, which previously have not been reported using N-carbamoyl-imines with simple ketone enolates, became our objective. In this report, we describe the first direct catalytic Mannich-type reaction between various ynones and N-Boc imines, whose stereocontrol presumably derives from catalyst control of enolate geometry. This method produces α-substituted β-amino ynones with excellent chemo-, diastereo-, and enantioselectivity. The products can be readily transformed into a broad range of molecular scaffolds upon further one-step transformations, demonstrating the utility of ynones as masked synthetic equivalents for a variety of unsymmetrically substituted acyclic ketones. In particular, alkynyl alkyl ketones resolve the long-standing problem of the inability to use the enolates of unsymmetrical dialkyl ketones lacking α-branching for regio- and stereoselective reactions.
Collapse
Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
| | - Chao-I (Joey) Hung
- Department of Chemistry, Stanford University, Stanford, California 94305-5580, United States
| |
Collapse
|
9
|
Allais C, Tsai AS, Nuhant P, Roush WR. Generation of stereochemically defined tetrasubstituted enolborinates by 1,4-hydroboration of α,β-unsaturated morpholine carboxamides with (diisopinocampheyl)borane. Angew Chem Int Ed Engl 2013; 52:12888-12891. [PMID: 24281884 PMCID: PMC3910328 DOI: 10.1002/anie.201307302] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 09/15/2013] [Indexed: 11/10/2022]
Abstract
On all fours: The title reaction with (Ipc)2 BH provides tetrasubstituted enolborinates which undergo aldol reactions with aldehydes to form products with all-carbon quaternary centers with exceptional diastereo- and enantioselectivity. A change to the substitution pattern of the starting amide leads to either diastereomer of the α-methyl-α-ethyl-β-hydroxy carboxamide (1 or 2).
Collapse
Affiliation(s)
- Christophe Allais
- Department of Chemistry The Scripps Research Institute 130 Scripps Way,
3A2, Jupiter FL 33458 (USA)
| | - Andy S. Tsai
- Department of Chemistry The Scripps Research Institute 130 Scripps Way,
3A2, Jupiter FL 33458 (USA)
| | - Philippe Nuhant
- Department of Chemistry The Scripps Research Institute 130 Scripps Way,
3A2, Jupiter FL 33458 (USA)
| | - William R. Roush
- Department of Chemistry The Scripps Research Institute 130 Scripps Way,
3A2, Jupiter FL 33458 (USA)
| |
Collapse
|
10
|
Allais C, Nuhant P, Roush WR. (Diisopinocampheyl)borane-mediated reductive aldol reactions of acrylate esters: enantioselective synthesis of anti-aldols. Org Lett 2013; 15:3922-5. [PMID: 23885946 DOI: 10.1021/ol401679g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The (diisopinocampheyl)borane promoted reductive aldol reaction of acrylate esters 4 is described. Isomerization of the kinetically formed Z(O)-enolborinate 5Z to the thermodynamic E(O)-enolborinate 5E via 1,3-boratropic shifts, followed by treatment with representative achiral aldehydes, leads to anti-α-methyl-β-hydroxy esters 9 or 10 with excellent diastereo- (up to ≥20:1 dr) and enantioselectivity (up to 87% ee). The results of double asymmetric reactions of 5E with several chiral aldehydes are also presented.
Collapse
Affiliation(s)
- Christophe Allais
- Department of Chemistry, Scripps Florida, Jupiter, Florida 33458, USA
| | | | | |
Collapse
|
11
|
Nuhant P, Allais C, Roush WR. Diisopinocampheylborane-mediated reductive aldol reactions: highly enantio- and diastereoselective synthesis of syn aldols from N-acryloylmorpholine. Angew Chem Int Ed Engl 2013; 52:8703-7. [PMID: 23818095 DOI: 10.1002/anie.201302535] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Philippe Nuhant
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, 3A2, Jupiter, FL 33458, USA
| | | | | |
Collapse
|
12
|
Hassan A, Krische MJ. Unlocking Hydrogenation for C-C Bond Formation: A Brief Overview of Enantioselective Methods. Org Process Res Dev 2011; 15:1236-1242. [PMID: 22125398 PMCID: PMC3224080 DOI: 10.1021/op200195m] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydrogenation of π-unsaturated reactants in the presence of carbonyl compounds or imines promotes reductive C-C coupling, providing a byproduct-free alternative to stoichiometric organometallic reagents in an ever-increasing range of C=X (X = O, NR) additions. Under transfer hydrogenation conditions, hydrogen exchange between alcohols and π-unsaturated reactants triggers generation of electrophile-nucleophile pairs, enabling carbonyl addition directly from the alcohol oxidation level, bypassing discrete alcohol oxidation and generation of stoichiometric byproducts.
Collapse
Affiliation(s)
- Abbas Hassan
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station – A5300, Austin, TX 78712-1167, USA
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station – A5300, Austin, TX 78712-1167, USA
| |
Collapse
|
13
|
Sabirova JS, Haddouche R, Van Bogaert IN, Mulaa F, Verstraete W, Timmis KN, Schmidt-Dannert C, Nicaud JM, Soetaert W. The 'LipoYeasts' project: using the oleaginous yeast Yarrowia lipolytica in combination with specific bacterial genes for the bioconversion of lipids, fats and oils into high-value products. Microb Biotechnol 2011; 4:47-54. [PMID: 21255371 PMCID: PMC3815794 DOI: 10.1111/j.1751-7915.2010.00187.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Accepted: 04/25/2010] [Indexed: 11/28/2022] Open
Abstract
The oleochemical industry is currently still dominated by conventional chemistry, with biotechnology only starting to play a more prominent role, primarily with respect to the biosurfactants or lipases, e.g. as detergents, or for biofuel production. A major bottleneck for all further biotechnological applications is the problem of the initial mobilization of cheap and vastly available lipid and oil substrates, which are then to be transformed into high-value biotechnological, nutritional or pharmacological products. Under the EU-sponsored LipoYeasts project we are developing the oleaginous yeast Yarrowia lipolytica into a versatile and high-throughput microbial factory that, by use of specific enzymatic pathways from hydrocarbonoclastic bacteria, efficiently mobilizes lipids by directing its versatile lipid metabolism towards the production of industrially valuable lipid-derived compounds like wax esters (WE), isoprenoid-derived compounds (carotenoids, polyenic carotenoid ester), polyhydroxyalkanoates (PHAs) and free hydroxylated fatty acids (HFAs). Different lipid stocks (petroleum, alkane, vegetable oil, fatty acid) and combinations thereof are being assessed as substrates in combination with different mutant and recombinant strains of Y. lipolytica, in order to modulate the composition and yields of the produced added-value products.
Collapse
Affiliation(s)
- Julia S Sabirova
- Department of Bioscience and Bioengineering, Ghent University, Ghent, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Zhou L, Doyle MP. Stereoselective synthesis of highly functionalized alpha-diazo-beta-ketoalkanoates via catalytic one-pot Mukaiyama-Aldol reactions. Org Lett 2010; 12:796-9. [PMID: 20102172 PMCID: PMC2829718 DOI: 10.1021/ol902872y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methyl diazoacetoacetate undergoes zinc triflate catalyzed condensation with a broad selection of aldehydes to produce delta-siloxy-alpha-diazo-beta-ketoalkanoates in good yield, and delta-hydroxy-alpha-diazo-beta-ketoalkanoates are formed with high diastereoselectivity in reactions with alpha-diazo-beta-ketopentanoate promoted by dibutylboron triflate.
Collapse
Affiliation(s)
- Lei Zhou
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Michael P. Doyle
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| |
Collapse
|
15
|
Lu Y, Kim IS, Hassan A, Del Valle DJ, Krische MJ. 1,n-glycols as dialdehyde equivalents in iridium-catalyzed enantioselective carbonyl allylation and iterative two-directional assembly of 1,3-polyols. Angew Chem Int Ed Engl 2009; 48:5018-21. [PMID: 19472247 DOI: 10.1002/anie.200901648] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Unstable? We're able! 1,n-Glycols serve as synthetic equivalents to unstable dialdehydes in two-directional carbonyl allylation from the alcohol oxidation level under iridium-catalyzed transfer hydrogenation conditions. Iterative asymmetric allylation employing 1,3-propanediol enables the rapid assembly of protected 1,3-polyol substructures with exceptional levels of stereocontrol.
Collapse
Affiliation(s)
- Yu Lu
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station-A5300, Austin, TX 78712-1167, USA
| | | | | | | | | |
Collapse
|
16
|
Han SB, Kim IS, Han H, Krische MJ. Enantioselective carbonyl reverse prenylation from the alcohol or aldehyde oxidation level employing 1,1-dimethylallene as the prenyl donor. J Am Chem Soc 2009; 131:6916-7. [PMID: 19453190 DOI: 10.1021/ja902437k] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enantioselective transfer hydrogenation of 1,1-dimethylallene 1a in the presence of aromatic, alpha,beta-unsaturated, or aliphatic aldehydes 2a-i mediated by 2-propanol and employing a cyclometalated iridium C,O-benzoate derived from allyl acetate, m-nitrobenzoic acid, and (S)-SEGPHOS delivers reverse-prenylation products 4a-i in good to excellent isolated yields (65-96%) and enantioselectivities (87-93% ee). In the absence of 2-propanol, enantioselective carbonyl reverse prenylation is achieved directly from the alcohol oxidation level to furnish an equivalent set of adducts 4a-i in good to excellent isolated yields (68-94%) and enantioselectivities (86-91% ee). Competition and isotopic labeling experiments suggest rapid alcohol-aldehyde redox equilibration in advance of carbonyl addition along with capture of the kinetically formed pi-allyl complex at a higher rate than reversible beta-hydride elimination-hydrometalation. This protocol represents an alternative to the use of allylmetal reagents in enantioselective carbonyl reverse prenylation and represents the first use of allenes in enantioselective C-C bond-forming transfer hydrogenation.
Collapse
Affiliation(s)
- Soo Bong Han
- University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, Texas 78712, USA
| | | | | | | |
Collapse
|
17
|
Itoh J, Han SB, Krische MJ. Enantioselective allylation, crotylation, and reverse prenylation of substituted isatins: iridium-catalyzed C-C bond-forming transfer hydrogenation. Angew Chem Int Ed Engl 2009; 48:6313-6. [PMID: 19606435 PMCID: PMC2846777 DOI: 10.1002/anie.200902328] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Transfer hydrogenation of substituted isatins in the presence of allyl acetate, α-methyl allyl acetate or 1,1,-dimethylallene employing an ortho -cyclometallated iridium catalyst modified by CTH-(R )-P-PHOS provides products of carbonyl allylation, crotylation and reverse prenylation, respectively, in highly enantiomerically enriched form. These studies represent the first use of activated ketones as electrophilic partners in asymmetric C-C bond forming transfer hydrogenation.
Collapse
Affiliation(s)
- Junji Itoh
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station – A5300, Austin, TX 78712-1167 (USA)
| | - Soo Bong Han
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station – A5300, Austin, TX 78712-1167 (USA)
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station – A5300, Austin, TX 78712-1167 (USA)
| |
Collapse
|
18
|
Ghosh AK, Kass J, Anderson DD, Xu X, Marian C. L-selectride-mediated highly diastereoselective asymmetric reductive aldol reaction: access to an important subunit for bioactive molecules. Org Lett 2008; 10:4811-4. [PMID: 18831554 DOI: 10.1021/ol801971t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
L-selectride reduction of a chiral or achiral enone followed by reaction of the resulting enolate with optically active alpha-alkoxy aldehydes proceeded with excellent diastereoselectivity. The resulting alpha,alpha-dimethyl-beta-hydroxy ketones are inherent to a variety of biologically active natural products.
Collapse
Affiliation(s)
- Arun K Ghosh
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| | | | | | | | | |
Collapse
|