The chemistry of higher order organocuprates

Lipshutz, Bruce H.; Wilhelm, Robert S.; Kozlowski, Joseph A.

doi:10.1016/s0040-4020(01)91251-7

Cited by 361 publications

(89 citation statements)

References 130 publications

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“…A possible reason for the increased diastereoselectivity observed with compounds 16-18 may be due to an unfavourable 1,3-diaxial interaction, which would exist between the C-3 side-chain methyl group and the oxygen atom of the ether bridge if the methyl group were axial in adducts [22][23][24] (Fig. 1); this 1,3-diaxial interaction is absent in adducts 19-21.…”

Section: Imdaf Reactions With Florisil In Rnethylene Chloridementioning

confidence: 99%

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

Rogers¹,

Keay²

1993

Can. J. Chem.

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The diastereoselective intramolecular Diels-Alder reactions of the furan diene (IMDAF), in which the side arm comprises four carbon atoms and is substituted by a methyl group adjacent to, or one carbon removed from, the furan ring, are described. Adducts are formed in moderate to excellent yields when treated with either Florisil in methylene chloride at room temperature or methylaluminum dichloride in methylene chloride at -78°C. Florisil is most effective for substrates containing unsubstituted dienophiles. An equimolar quantity (1.1 equivalents) of methylaluminum dichloride is most effective for precursors having methacrolein-type dienophiles, while a catalytic quantity (0.1 equivalent) is effective for crotonaldehyde-type dienophiles. Only the adducts with the side arm orientated syn with respect to the oxygen bridge are detected and isolated. The major diastereomer is the one in which the methyl group (initially on the side arm) is situated equatorially on the newly formed six-membered ring. An application of the diastereoselective IMDAF reaction to the synthesis of (*)-l,4-epoxycadinane is described, beginning with 2-methylfuran.CHRISTINE ROGERS et BRIAN A. KEAY. Can. J. Chem. 71, 6 1 1 (1993).On dCcrit les reactions diastCrCosClectives de Diels-Alder intramolCculaires du furane (DAIMF) agissant comme diene et dans lequel la chaine laterale comporte quatre atomes de carbone et est substituke par un groupe mCthyle sur le carbone en a ou en p par rapport au noyau furanique. Les addults se forment avec des rendements allant de moyens a excellent~ lorsqu'on les traite soit avec du Florisil dans le chlorure de mCthylkne 2 la tempCrature ambiante soit avec du dichlorure de mCthylaluminium dans le chlorure de mCthylkne a -78°C. Le Florisil est le plus efficace pour les substrats contenant des diknophiles qui ne sont pas substitues. Une quantitC Cquimolaire (1,l equivalents) de dichlorure de mCthylaluminium est le plus efficace pour des diknophiles precurseurs du type mCthacrolCine alors qu'une quantitC catalytique (0,l equivalent) est efficace pour les dienophiles du type crotonaldChyde. On n'a detect6 et isolC que les adduits dont la chaine 1atCrale est orientCe en syrl par rapport au pont oxygCnC. Le diastereoisomkre principal est celui dans lequel le groupe mkthyle (initialement dans la chaine IatCrale) est en position Cquatoriale dans le cycle i six chainons nouvellement forme. On dCcrit une application de la rCaction diastCrCosClective Diels-Alder intramolCculaire du furane pour la synthkse du ( 2 ) -I ,4-6poxycadinane a partir du 2-mCthylfurane. [Traduit par la rCdaction]The intramolecular Diels-Alder reaction of the furan diene (IMDAF) has been studied by many groups since it was fust reported in 1978 (1). These investigations have attempted to define the scope and limitations of the LMDAF reaction with respect to (i) the effect of varying the length of the tether linking the diene and d i e n~~h i l e , ' .~(ii) the effect of substituting heteroatoms for carbon on the t e t h e~-,~.~ (iii) the effect of v...

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Section: Imdaf Reactions With Florisil In Rnethylene Chloridementioning

confidence: 99%

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

Rogers¹,

Keay²

1993

Can. J. Chem.

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“…This was in agreement with the recent findings by Vermeer [l Oa] and the Scheringgroup [l Ob] ,who confirmed the original stereochemical result (anti) reported by Crabbe [3c] . In this article, we report the full account of our preliminary communication [9] and describe new investigations of the substrates 3b-d and 4b-d with other Gilman-type reagents as well as the convenient higher-order mixed cuprate system described by Lipshutz [11] . RESULTS …”

Section: Qf'mentioning

confidence: 99%

“…The first of these was the Gilman-type reagent (R 2CuLi) [16], prepared by addition of two moles of the appropriate commercially available organolithium reagent to one mole of purified (via the dimethyl sulfide complex) [17] copper iodide. The second organocopper system used was Lipshutz's higher-order mixed cuprate reagent [R 2Cu(CN)Li2 ] [11], which is prepared in a fashion similar to the Gilman reagent except cuprous cyanide is used instead of the iodide. Upon treatment of benzoates 3b and 4b with these reagents, the corresponding allenes were obtained (Table 2).…”

Section: Propargylic Substratesmentioning

confidence: 99%

On the Stereochemistry of Organocopper Mediated Conversion of Propargylic Esters to Allenes

Haces

KRUCHTEN

Okamura

1985

Israel Journal of Chemistry

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Abstract. Using a vitamin D-related steroidal CD fragment as a stereochemical probe, the effect of various factors on the stereochemical course of the organocopper induced conversion of propargylic esters to allenes has been studied. In all cases, an anti mode of attack by the organocopper species was found to be preferred. The effectiveness of Gilman-type reagents (R 2CuLi) versus that of the Lipshutz-type higher-order mixed cuprate systems (R 2CuCNLi 2 ) in promoting the reaction was also studied.

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“…Subsequently, the addition of 2 equivs of an organolithium reagent LiR to CuCN was reported 5 to give a new type of highly reactive organocyanocuprate reagent of the proposed formula Li 2 -[Cu(CN)R 2 ] in which the two R groups and CN − ligand were assumed to be bound directly to copper to give a "higherorder" cyanocuprate. 6 The structures of these interesting species have been the focus of intensive study. Initial investigation by 13 C NMR spectroscopy seemed that the CN − group was bound to copper.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of (THF)₃Li(NC)CU(C₆H₃-2,6-Mes₂)and Br(THF)₂Mg(C₆H₃-2,6-Trip₂) (Mes = C₆H₂-2,4,6-Me₃; Trip = C₆H₂-2,4,6-i-Pr₃): The Structures of a Monomeric Lower-Order Lithi

2003

Bulletin of the Korean Chemical Society

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The lower-order lithium organocyanocuprate compound, (THF) 3 Li(NC)Cu(C 6 H 3 -2,6-Mes 2 ) (1), and the bulky terphenyl Grignard reagent, Br(THF) 2 Mg(C 6 H 3 -2,6-Trip 2 ) (2), have been synthesized and structurally characterized both in the solid state by single crystal x-ray crystallography and in solution by multi-nuclear NMR and IR spectroscopy. The compound (1) was isolated as a monomeric contact ion-pair in which the C (organic ipso)-Cu-CN-Li atoms are coordinated linearly. The lithium has a tetrahedral geometry as a result of solvation by three THF molecules. The compound (1) is the first example of fully characterized monomeric lower order lithium organocyanocuprate. The bulky Grignard reagent (2) was also isolated as a monomer in which the magnesium, solvated by two THF molecules, has a distorted tetrahedral geometry. The crystals of (1)

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The chemistry of higher order organocuprates

Cited by 361 publications

References 130 publications

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

On the Stereochemistry of Organocopper Mediated Conversion of Propargylic Esters to Allenes

Synthesis and Characterization of (THF)₃Li(NC)CU(C₆H₃-2,6-Mes₂)and Br(THF)₂Mg(C₆H₃-2,6-Trip₂) (Mes = C₆H₂-2,4,6-Me₃; Trip = C₆H₂-2,4,6-i-Pr₃): The Structures of a Monomeric Lower-Order Lithi

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The chemistry of higher order organocuprates

Cited by 361 publications

References 130 publications

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

Diastereoselective intramolecular Diels–Alder reactions of the furan diene: the synthesis of (±)-1,4-epoxycadinane

On the Stereochemistry of Organocopper Mediated Conversion of Propargylic Esters to Allenes

Synthesis and Characterization of (THF)3Li(NC)CU(C6H3-2,6-Mes2)and Br(THF)2Mg(C6H3-2,6-Trip2) (Mes = C6H2-2,4,6-Me3; Trip = C6H2-2,4,6-i-Pr3): The Structures of a Monomeric Lower-Order Lithi

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Synthesis and Characterization of (THF)₃Li(NC)CU(C₆H₃-2,6-Mes₂)and Br(THF)₂Mg(C₆H₃-2,6-Trip₂) (Mes = C₆H₂-2,4,6-Me₃; Trip = C₆H₂-2,4,6-i-Pr₃): The Structures of a Monomeric Lower-Order Lithi