Peterson Olefination Research Articles

Efficient and selective synthesis of 6,7-Dehydrostipiamide via Zr-catalyzed asymmetric carboalumination and Pd-catalyzed cross-coupling of organozincs.

[structure: see text] 6,7-Dehydrostipiamide has been synthesized in 23% yield in 15 steps in the longest linear sequence through the application of the Zr-catalyzed asymmetric carboalumination and the Pd-catalyzed organozinc cross-coupling in addition to the Brown crotylboration, the Corey-Peterson olefination, and the Corey-Fuchs reaction for carbon-carbon bond formation.

Scope and Limitations of the Peterson Olefination Reaction as a Route to Vinylidene Phosphanes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Asymmetric Reactions Based on Activation and Structure Control of Molecule — Asymmetric Reaction of Lithiated Nucleophiles

AbstractFor Abstract see ChemInform Abstract in Full Text.

Silenes as Novel Synthetic Reagents: Synthesis of Diols and Lactones from Simple Alkyldienes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Scope and Limitations of the Peterson Olefination Reaction as a Route to Vinylidene Phosphanes

AbstractThe Peterson olefination reaction has been investigated as a route to novel P‐substituted alkenes. The reaction between [(nPr2P)2(Me3Si)C]Li and paraformaldehyde cleanly gives the symmetrical vinylidene phosphane (nPr2P)2C=CH2 (4) in good to excellent yields. In contrast, reactions between [(R2P)(Me3Si)2C]Li (R = Me, nPr) and paraformaldehyde yield complex mixtures of products which do not contain the expected vinylidene species. However, the unsymmetrical vinylidene phosphanes [nPr2P(BH3)](Me3Si)C=CH2 (6), (Ph2P)(iPr2P)C=CH2 (7), [nPr2P(S)](Me3Si)C=CH2 (10), [Ph2P(S)][iPr2P(S)]C=CH2 (11) and [Ph2P(S)][Me2P(S)]C=CH2 (12) are readily accessible by the Peterson olefination reaction {compound 7 is obtained by deprotection of the corresponding borane adduct [Ph2P(BH3)][iPr2P(BH3)]C=CH2 with pyrrolidine}. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Synthesis of Δ 12,14-15-deoxy-PG-J 1 methyl ester and epi-Δ 12-15-deoxy-PG-J 1

The synthesis of racemic Δ 12,14-15-deoxy-PG-J 1 is readily achieved in six steps employing as the key transformation a one-pot conjugate addition–Peterson olefination sequence using exo-2-trimethylsilyl-3a,4,7,7a-tetrahydro-4,7-methanoinden-1-one. Additionally a Noyori-type three-component coupling approach is employed for the synthesis of enantioenriched epi-Δ 12-15-deoxy-PG-J 1 from 4( S)- tert-butyldimethylsilyloxycyclopent-2-enone.

Asymmetric reactions based on activation and structure control of molecule--asymmetric reaction of lithiated nucleophiles

The methodology we developed relies on an external chiral coordinating reagent that forms a deaggregated chelate complex with organolithium reagents. Under the positive control of a chiral dimethyl ether of stilbenediol 4, an asymmetric conjugate addition reaction of organolithium reagents with unsaturated imines and esters proceeded successfully to yield the corresponding addition products with reasonably high stereoselectivity. The sense of stereochemistry is predictable based on a coordination model. The methodology has been extended to a catalytic asymmetric 1,2-addition reaction of organolithium reagents with imines. An enantiotopic group differentiating the opening of cyclohexene oxide with organolithium was also mediated by a chiral ligand. The asymmetric Horner-Wadsworth-Emmons reaction of phosphonates and Peterson reaction of alpha-silylester with 4-substituted cyclohexanone were another successful extension of the methodology. A three-component reagent of lithium ester enolate, lithium amide, and chiral diether reacts with imines to afford beta-lactam with reasonably high enantioselectivity. Tridentate aminoether ligands were also shown to affect the catalytic asymmetric addition of lithium ester enoaltes to imines, giving beta-lactams with high enantioselectivity. Asymmetric conjugate addition of lithium amide to enoates was mediated by a chiral diether ligand to give the beta-aminoester with high yield and enatioselectivity. The methodology has been successfully applied to an asymmetric synthesis of biologically potent compounds. Dihydrexidine, a promising anti-Parkinsonism candidate, and salsolidine, a representative isoquinoline alkaloid, have been synthesized using asymmetric addition reactions of organolithium reagents as the key steps.

Highly Efficient Peterson Olefination Leading to Unsaturated Selenoamides and Their Characterization.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A New Synthesis of α‐Fluorovinylsulfones Utilizing the Peterson Olefination Methodology.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Silenes as novel synthetic reagents: identification of a practical method for silene generation and trapping.

The elucidation of a robust and reliable sequence for the generation of highly reactive transient silenes from simple aldehydes is described. The key step involves a silyl-modified Peterson olefination which critically depends on the presence of a sub-stoichiometric amount of soluble lithium salts (LiBr).

Synthetic protocols, molecular polarity, and 13C NMR correlations for 1-aryl- and 1-diarylmethylidene-1H-cyclopropa[b]naphthalenes

The Peterson olefination for alkylidenecycloproparene synthesis from a 1,1-disilylcycloproparene has been refined into five distinct protocols that have provided 43 new aryl- (5 and 6) and diaryl- (7 and 8), and aryl(phenyl)- (9 and 10) methylidene derivatives. The permanent dipole moments of these and other previously reported compounds have been measured and the direction of the dipole, to or from the cycloproparenyl moiety, established for each compound. The 13C NMR spectra are fully assigned and linear correlations of carbon chemical shift with the Hammett sigmap+ constants for each atom within the cycloproparene moiety are provided for the 8-11 compounds that comprise each substitution pattern present in 5-10.

Stereochemistry of the reaction of Si-phenyl silenes with butadienes: elaboration of the silacycloadducts to provide a novel route to substituted lactones.

Silenes generated through a silyl-modified Peterson olefination procedure can be trapped with a range of alkyl butadienes via a [4 + 2] cycloaddition pathway to afford silacycles accompanied by variable amounts of competing ene, [2 + 2] and silene dimer by-products. The silacycles are formed with good chemo- and stereo-selectivity and provide access to diols and lactones via a phenyl-triggered Fleming-Tamao oxidation.

Conjugated and Cross‐Conjugated π‐Extended Cycloproparenes with Dithiole and Cyclopentadiene Functionality

AbstractDithiole and cyclopentadiene rings have been introduced into functionalised cyclopropa[b]naphthalenes to provide highly coloured, conjugated and cross‐conjugated π‐extended derivatives that have varying stability. Cyclopentadienylidene‐containing cyclopropanaphthalene 18 and its dithiolylidene analogue 25 are prepared from bromophenylcyclopropanaphthalene 12, and the 1,1‐biscyclopentadienylidene 20 from dibromide 13. Use of dithiole‐containing ketones with 1,1‐bis(trimethylsilyl)cyclopropa[b]naphthalene 10 gives the π‐extended cycloproparenes 27 and 29 in Peterson olefinations that are more efficient than Wittig−Horner reactions of cyclopropanthraquinone 31 with dithiolate 24 to give the cross‐conjugated cycloproparenes 34 and 35. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Large-Scale Synthesis of the Anti-Cancer Marine Natural Product (+)-Discodermolide. Part 4: Preparation of Fragment C7-24

Coupling of C9-14 (4) and C15-21 (5a) fragments to produce the cis-trisubstituted olefin was achieved using Suzuki-type coupling conditions employed by Marshall (5a/tert-BuLi/B-OMe-9-BBN added to 4/Cs2CO3/Pd(dppf)2). The terminal (Z)-diene moiety was attached to aldehyde 10 by using a sequential Nozaki−Hiyama allylation and Peterson olefination sequence; careful monitoring of the disappearance of both diastereomeric β-hydroxysilanes was found to be essential for achieving a high yield. In the oxidation of alcohols 12 and 16 to 13 and 7, respectively, using iodobenzene diacetate and TEMPO, addition of a trace of water was found to be crucial for complete conversion. The C8-9 (Z)-olefin functionality was introduced on to aldehyde 13 using a Still−Gennari HWE reaction. Subsequent carbamate installation at C-19 followed by a reduction/oxidation sequence gave the title fragment C7-24 (7) ready to be coupled with the C1-6 fragment, which is described in Part 2 of this series.

Silenes as novel synthetic reagents: synthesis of diols and lactones from simple alkyldienes

Aryl substituted silenes can be generated by a modified Peterson olefination reaction and trapped in situ to afford silacycles with high diastereoselectivity. These silacycles can be elaborated by ‘Fleming–Tamao’ type oxidation to provide access to functionalized diols and lactones.

Studies in the Cycloproparene Series: Unexpected Products from Peterson Olefinations

AbstractReaction of tetraphenylcyclopentadienone with anion 8 derived by monodesilylation of 1,1‐bis(trimethylsilyl)cyclopropa[b]naphthalene (10) gives the 1‐(5′‐cyclopentadienyl)‐substituted cycloproparene 17 from simple anion addition to the carbonyl group rather than fulvalene 16 from loss of Me3SiO−. Reactions of anion 8 with p‐(trifluoromethyl)benzaldehyde and thiophene‐2‐carbaldehyde give the expected exocyclic olefins 12a and 12b, respectively. In contrast, the 3,6‐dimethoxy analogue 24, obtained from cycloproparene 20, gives the C1 unsubstituted cycloproparene 19 and the Tishchenko products, p‐(trifluoromethyl)benzyl p‐(trifluoromethyl)benzoate (21) and 2‐thienylmethyl thiophene‐2‐carboxylate (22), respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Cover Picture: Studies in the Cycloproparene Series: Unexpected Products from Peterson Olefinations (Eur. J. Org. Chem. 23/2003)

AbstractThe cover picture shows the computed density potential (left) for the expected calicene from Peterson olefination of 1,1‐disilylcyclopropa[b]naphthalene with tetracyclone. The alcohol actually obtained from the reaction is shown on the right in its favoured conformation. Details are discussed in the article by B. Halton et al. on p. 4507 ff.

Conjugate Addition—Peterson Olefination Reactions: Expedient Routes to Cross Conjugated Dienones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Formation of 1‐Ethenylcyclopropanols Involving Kulinkovich Cyclopropanation and Peterson Olefination of α‐Trimethylsilylesters.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A new synthesis of α-fluorovinylsulfones utilizing the Peterson olefination methodology

α-Fluoro-α-silyl-substituted sulfones 1 are readily prepared from fluoromethyl phenyl sulfone and the appropriate silyl chloride. The use of TBSCl improves both the stability and yield of 1. Lithium derivatives 4 undergo a smooth Peterson olefination reaction with less-enolizable carbonyl compounds to give moderate to good yields of the expected α-fluorovinylsulfones 6, in some cases with high E-stereoselectivity. One-pot reaction with 4 generated in situ from fluoromethyl phenyl sulfone in tetrahydrofuran (THF) also proceeds smoothly, particularly with aldehydes.