Metallo aldimines. II. A versatile synthetic intermediate

Walborsky, H. M.; Morrison, W. H.; Niznik, G. E.

doi:10.1021/ja00725a068

Cited by 63 publications

(10 citation statements)

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“…The hydrocarbon 5 was identified by comparison with the ir and nmr spectra of the authentic material and by vpc peak enhancement (20% EGIP on 80/100 Chromasorb P, AW), [a]26546i + 18.0 ± 0.5°. The ketone 6 showed the following properties: ir (CC14) 1720 cm-1 (s) (lit.11 1715 cm"1); nmr (CDClg) 2.06 (s, 3, CH3), 3.20 (d, 2, J = 7.5 Hz, CH2), 4.71 (t, 1 , J = 7.5 Hz, CH), 7.42 (s, 10, aromatic); 2,4-DNP mp 173-175°(lit.12 mp 174-175°). The cyclobutane 2 showed the following properties: ir (CC14) 1783 (s), 1494 (m), 1450 (m), 692 cm-1 (s); nmr (CDC13) 1.32 (d, 3, J = 7 Hz, CH3), 2.37 (m, 1, JAB = 10.5, JAX = 8 Hz, HCH), 3.09 (m, 1, JAB = 10.5, JBX = 10.5 Hz, HCH), 3.32 (m, 1, CH), 7.0-7.5 (m, 10, aromatic); ir irradiation at 1.32, 3.32 (m, JAX = 8, JBX = 10.5 Hz); irradiation at 3.32, 2.37 (d, JAB = 10.5 Hz); mass spectrum m/e (caled mass) 235.1199 (caled for CirHieO, 236,1200), 237.1219 (caled for Ci613CH160, 237.1234), 208.1274 (caled for CieHie, 208.1292), 181.1020 (caled for C14H13, 181.1017), 166.0778 (caled for C13H10, 166.0782); 2,4-DNP mp 207-208°.…”

Section: Experimental Section9mentioning

confidence: 99%

Cyclopropanes. XXXIV. Ring enlargements and rearrangements from carbanionic .alpha. additions to isocyanides

Niznik¹,

Walborsky²

1974

J. Org. Chem.

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The reaction of 1-methyl-2,2-diphenylcyclopropyllithium (1) with 1,1,3,3-tetramethylbutyl isocyanide resulted in a ring enlargement to yield 2,2-diphenyl-4-methylcyclobutanone (2). A similar ring enlargement was observed when l-methyl-2,2-diphenylcyclopropyl isocyanide (4) was treated with lithium or sodium metal in dimethoxyethane. In this latter reaction one also obtained an equal amount of rearranged 4,4-diphenyl-2-butanone (6). Reaction of 4 with a solution of sodium in liquid ammonia produced 1,1-diphenylbutane (10) and 2methyl-4,4-diphenylpyrolidine (11). Reaction pathways leading to the formation of the ring-expanded and rearranged products are discussed.We have previously shown that the addition of lithium alkyls to isocyanides leads to the formation of lithium aldimines.2 The lithium aldimine intermediate can be used for the preparation of 1-d-aldehydes, ketones, -keto acids and esters, and a-and (3-hydroxy ketones.3 However, we found that 2,2-diphenyl-l-methylcyclopropyllithium (1) did not undergo a simple a addition to 1,1,3,3-tetrameth-

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Section: Experimental Section9mentioning

confidence: 99%

Cyclopropanes. XXXIV. Ring enlargements and rearrangements from carbanionic .alpha. additions to isocyanides

Niznik¹,

Walborsky²

1974

J. Org. Chem.

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“…[8,9] On the contrary, reactions initiated by its electrophilicity are rare. [10,11] As a continuation of our studies on the development of isonitrile-based novel transformations, [12] we became interested in Lewis acid mediated reactions between isonitriles and nucleophiles. [13] We report herein that in the presence of ZnBr 2 , the reaction between isonitriles 1 and carboxylic acids 2 deviated completely from the a-addition/1,3-acyl-shift sequence [Eq.…”

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confidence: 99%

Zinc Bromide Promoted Coupling of Isonitriles with Carboxylic Acids To Form 2,4,5‐Trisubstituted Oxazoles

et al. 2013

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Deviant behavior: In a deviation from “normal” reactivity, isocyanides underwent co‐trimerization with carboxylic acids in the presence of ZnBr2 to smoothly provide oxazoles (see scheme). The reaction is thought to occur by initial nucleophilic addition of the carboxylic acid to a ligated isonitrile molecule, followed by a sequence involving double migratory insertion, metal‐salt elimination, acyl migration, cyclization, and dealkylation.

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“…The addition of organolithium compounds to isonitriles is subject to various side reactions, notably -deprotonation (Walborsky et al, 1970(Walborsky et al, , 1971Niznik et al, 1974;Hirowatari & Walborsky, 1974;Niznik & Walborsky, 1974;Periasamy & Walborsky, 1974). In the absence of -H atoms, however, isonitriles show carbene-like reactivity, giving lithioimines; subsequent reaction with electrophiles gives imine derivatives, which may be desired in their own right (Walborsky & Roman, 1978; Barluenga et al, 1988;Ito et al, 1984).…”

Section: Commentmentioning

confidence: 99%