Harold W. Moore

Bio: Harold W. Moore is an academic researcher from University of California, Irvine. The author has contributed to research in topics: Cycloaddition & Ring (chemistry). The author has an hindex of 29, co-authored 192 publications receiving 3272 citations.

Cyclobutenone-Based Syntheses of Polyquinanes and Bicyclo[6.3.0]undecanes by Tandem Anionic Oxy-Cope Reactions. Total Synthesis of (+/-)-Precapnelladiene.

Abstract: The addition of ethenyllithium derivatives to the carbonyl of dialkyl squarate-derived bicycloheptenones, e.g., 1a and 6a, initiates a low-temperature anion-accelerated oxy-Cope rearrangement to provide polyquinanes by a transannular aldol reaction of the intermediate bicyclo[6.3.0]undecadienone 4. Additional functionality is introduced by alkylation of the enolate 3 resulting from the oxy-Cope rearrangement. Phosphorylation or triflation of enolate 3 provides an entry into the bicyclo[6.3.0]undecane ring system. An application of this new methodology is demonstrated by the total synthesis of the sesquiterpene natural product (+/-)-precapnelladiene from diisopropyl squarate (10 steps, 12%).

Rearrangements of cyclobutenones. Conversion of selected 4-allylcyclobutenones to bicyclo[3.2.0]heptenones

Abstract: J . Org. Chem. 1989,54, 6018-6021 Scheme I11 TEST H --Co2Et v OAc c K-PH1 5 HI 1 x=o .c-- fi OAc X =aOAc;PH (i) DiBAH c (ii) Ph3P = CH (CH& QK from 12. The overall yield of 1 from 3 is 27%. As pre- viously described, 35J2 is readily available in enantiomer- ically homogeneous form from cis-l,4-diacetoxycyclo- pentene. The stereochemical outcome a t C13 arising from the coupling of similar substrates under the same conditions is amazing. In the previously described aldols5 leading to 5 and 6 no other stereoisomers were observed. Yet when the ynal 7 is employed 8 is the only product observed! Instead of offering ad hoc interpretations that do not flow from sound experimental observations, we prefer to outline an agenda of questions that must be addressed. Why does a particular substitution type on the aldehyde favor or disfavor silyl transfer? Is silyl transfer fundamental or accessory to the stereochemical outcome? Do the sharply differing results arise from a common transition-state (12) Cf: (a) Deardorff, D. R.; Myles, D. C.; MacFerrin, K . D. Tetra- hedron Lett. 1985, 5615. (b) Deardorff, D. R.; Matthews, A. J.; McMeekin, D. S.; Craney, C. L. Ibid. 1986, 1255. alignment differing in the placement of the R and H group of the aldehyde or do the reaction types differ in overall topography (chair vs boat, synclinal vs antiperiplanar)? Answers to these sorts of questions are not readily obtained but are crucial to illuminating this interesting stereo- chemical finding and extending it to new domains. I n the meantime, we note that the chemistry disclosed here and previously5 provides straightforward access to optically pure prostaglandins with complete control of the con- figuration at either C13 or C15 in any stereochemical sense. Acknowledgment. This research was supported by PHS Grant HL25848. NMR Spectra were obtained through the auspices of the Northeast Regional NSF/ NMR facility at Yale University, which was supported by NSF Chemistry Division Grant CHE 7916210. Supplementary Material Available: Experimental proce- dures and characterization data for all compounds (5 pages). Ordering information is given on any current masthead page. Rearrangements of Cyclobutenones. Conversion of Selected 4-Allylcyclobutenones to Bicycle[ 3.2.0lheptenones Simon L. Xu and Harold W . Moore* Department of Chemistry, University of California, Iruine, California 9271 7 Received October 9. 1989 Summary: 4-Allyl-4-alkoxy(or hydroxy or (trimethyl- sily1)oxy)cyclobutenones are reported to rearrange to bi- cyclo[3.2.0] hept-2-en-7-ones upon thermolysis in refluxing toluene. The synthetic scope and mechanism of this un- usual transformation are discussed. The products are envisaged to arise from an electrocyclic ring opening of the cyclobutenones to the corresponding vinylketenes which then undergo an intramolecular [ 2 21 cycloaddition of the ketene moiety to the nonconjugated allylic double bond. Sir: Selected 4-alkynyl, 4-alkenyl-, and 4-arylcyclo- butenones have recently been shown to undergo facile ring expansion to respectively benzoquinones, hydroquinones, 0 1989 American Chemical Society

Energy conservation in chemotrophic anaerobic bacteria.

Abstract: [This corrects the article on p. 100 in vol. 41.].

Dietary carcinogens and anticarcinogens Oxygen radicals and degenerative diseases

Abstract: The human diet contains a great variety of natural mutagens and carcinogens, as well as many natural antimutagens and anticarcinogens. Many of these mutagens and carcinogens may act through the generation of oxygen radicals. Oxygen radicals may also play a major role as endogenous initiators of degenerative processes, such as DNA damage and mutation (and promotion), that may be related to cancer, heart disease, and aging. Dietary intake of natural antioxidants could be an important aspect of the body’s defense mechanism against these agents. Many antioxidants are being identified as anticarcinogens. Characterizing and optimizing such defense systems may be an important part of a strategy of minimizing cancer and other age-related diseases.

A field guide to foldamers.

Abstract: III. Foldamer Research 3910 A. Overview 3910 B. Motivation 3910 C. Methods 3910 D. General Scope 3912 IV. Peptidomimetic Foldamers 3912 A. The R-Peptide Family 3913 1. Peptoids 3913 2. N,N-Linked Oligoureas 3914 3. Oligopyrrolinones 3915 4. Oxazolidin-2-ones 3916 5. Azatides and Azapeptides 3916 B. The â-Peptide Family 3917 1. â-Peptide Foldamers 3917 2. R-Aminoxy Acids 3937 3. Sulfur-Containing â-Peptide Analogues 3937 4. Hydrazino Peptides 3938 C. The γ-Peptide Family 3938 1. γ-Peptide Foldamers 3938 2. Other Members of the γ-Peptide Family 3941 D. The δ-Peptide Family 3941 1. Alkene-Based δ-Amino Acids 3941 2. Carbopeptoids 3941 V. Single-Stranded Abiotic Foldamers 3944 A. Overview 3944 B. Backbones Utilizing Bipyridine Segments 3944 1. Pyridine−Pyrimidines 3944 2. Pyridine−Pyrimidines with Hydrazal Linkers 3945

Organic Azides: An Exploding Diversity of a Unique Class of Compounds

Abstract: Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Cascade reactions in total synthesis.

Abstract: The design and implementation of cascade reactions is a challenging facet of organic chemistry, yet one that can impart striking novelty, elegance, and efficiency to synthetic strategies. The application of cascade reactions to natural products synthesis represents a particularly demanding task, but the results can be both stunning and instructive. This Review highlights selected examples of cascade reactions in total synthesis, with particular emphasis on recent applications therein. The examples discussed herein illustrate the power of these processes in the construction of complex molecules and underscore their future potential in chemical synthesis.