Tris cyclopropane, synthesis

Hudlicky developed a general method of tiiquinane synthesis based chi a cyclopropanation- arrange-ment sequence of dienic diazo ketones (Scheme 52). Topological selectivity of linear versus angular tri-quinane synthesis has been achieved. ... 

The full details of oxa-bis- and oxa-tris-a/ic-homobenzene syntheses, cw-aza-bis-and cis-aza-tris-a-homobenzene and cis-aza-tris-a-homotropilidene synthesis, and the decomposition of spiro[fluorene-9,3 -indazole] have become available, and there have been a number of routine applications of pyrazoline decomposition for cyclopropane synthesis. ... 

Trispiro[cyclopropane-l,2 2,2 3,2" -tris-l,3-benzodioxole] nomenclature, 1, 26 Tris-1,2,4-triazoles synthesis, 5, 745... 

A variety of functionalized [3]radialenes have been prepared starting from the appropriately substituted cyclopropanes or cyclopropenes. West and Zecher have pioneered the chemistry of [3]radialenes with quinoid substituents. The general strategy of this synthesis is outlined in Scheme 513. A tris(4-hydroxyphenyl)cyclopropenylium... 

More recently, Burgess et al. (34) used the same approach in the synthesis of a constrained phenylalanine derivative, 3-phenyl-2,3-methanophenylalanine (123). Libraries of metal complexes were screened to determine the best combination for the asymmetric cyclopropanation reaction (35). The ligands shown below were combined with AgSbFg, (CuOTf)2 PhH, RuC12(C10H14)]2, Sc(OTf)3, where tri-... 

Herrmann A, Ruettimann M, Thilgen C, Diederich F (1995) Multiple cyclopropanations of C70. Synthesis and characterization of bis-, tris-, and tetrakis-adducts and chiroptical properties of bis-adducts with chiral addends, including a recommendation for the configurational description of fullerene derivatives with a chiral addition pattern. Helv. Chim. Acta 78 1673-1704. 

The first example of a tether remote functionalization was the synthesis of the tris-64 (Scheme 10.14) [75,78]. For this purpose the computer-aided chemically designed addend 63 was allowed to undergo a successive nucleophilic cyclopropanation/ [4-1-2] cycloaddition sequence yielding the tris-adduct 64 in 60% yield with complete regio selectivity. Subsequent cyclopropanation of the remaining octahedral sites with a large excess of diethyl bromomalonate and DBU afforded the hexakisadduct 65... 

The tether directed cyclopropanations of Cjq discussed so far take advantage of specifically designed open-chain malonates with quite rigid spacers. This is a particularly suitable method for the synthesis of bisadducts. However, for an entry to tris- and higher adducts the design of a suitable steric arrangement becomes more and more difficult... 

The preparation of orthoformic acid esters from chloroform and alkali metal alkoxides is a long known procedure, " which can be performed under phase transfer catalysis. If small amounts of alcohol are present in the phase-catalyz process, cyclopropanes (372 Scheme 67) can be produced by aHHifinn of dichlorocarbene to l,2-dialkoxy-l,2-dichloroethylenes, which are thought to be intermediates. " Al-kenes of this kind, e.g. (373 equation 176), have been observed as byproducts in the synthesis of tri-r-butylorthoformate from chlorodifluoromethane or dichlorofluoromethane and potassium r-butoxide. Trimethoxyacetonitrile was prepared from trichloroacetonitrile and sodium methoxide. ... 

Offurtherinterest is a synthesis of cyclopropanes from allylic chlorides. Addition of diborane to allyl chloride in ether gives a mixture of mono-, di-, and tri (y-chlo-... 

The synthesis of tricarbonylchromium(O) complexes of mono-, di- and tri-substituted cyclopropanes, e.g. 150, has been accomplished through the reaction of tricarbonyl(styrene) chromium(O) complexes 151 with phosphorus and sulfur ylides. ... 

A variety of diverse synthetic methods have been empioyed for the preparation of cyclopropane (1 j. Schlatter and Demjanov and Dojarenko pyrolyzed cyclopropyltrimethylammonium hydroxide at 320°C using platinized asbestos as the catalyst. About equal amounts of cyclopropene (1) and cyclopropyidimethylamine are formed, contaminated with some dimethyl ether and ethylene. Treatment with dilute hydrochloric acid removed the amine from the gas stream and 1 was separated from the other products by gas chromatography. Alder-Rickert cleavage of the Diels-Alder adduct formed from cycloheptatriene and dimethyl acetylenedicarboxylate resulted only in the formation of a polymer and trace amounts of 1. A simple approach by Closs and Krantz based on the synthesis of 1-methylcyclopropene involved the addition of allyl chioride to a suspension of sodium amide in mineral oil at 80°C. Under the conditions employed, 1 could readily escape from the reaction mixture. Though a number of variations were tried, the yield of 1 never exceeded 10%. 

Simkhovich L, Mahammed A, Goldberg I, Gross Z (2001) Synthesis and characterization of germanium, tin, phosphorous, iron and rhodium complexes of tris(pentafluorophenyl)corrole, and the utilization of the iron and rhodium corroles as cyclopropanation catalysts. Chem Eur J 7 1041-1055... 

Tri-O-benzyl-D-glucose is an efficient and practical chiral auxiliary. If allylic alcohols are fixed as /3-glycosides they can be cyclopropanated by an excess of the diiodomethane/diethyl-zinc reagent with excellent diastereoselectivities. Since the removal of the auxiliary proceeds under mild conditions, this method allows the synthesis of a variety of cyclopropane carbinols in very high enantiomeric excesses96. 

Epoxide 303 has been used an an enantioselective synthesis of the methylenecyclopropa-neacetic acid (514a) portion of (methylenecyclopropyl)acetyl-CoA (514b), a mammalian metabolite of hypoglycines A and B. Addition of the anion derived from phenyl 2-(tri-methylsilyl)ethyl sulfone to 303 produces a 3 1 mixture of threo and erythro diastereomers 509. Either diastereomer cyclizes to the same cyclopropane 511 upon treatment with LDA, which suggests that epimerization at C-5 must be occurring prior to cyclization. Selective removal of the TBPS group followed by oxidation of the alcohol to an acid and elimination affords the desired product 514a (Scheme 73) [126,127]. 

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