Practical organic synthesis with strained ring molecules. Rhodium catalyzed carbonylation of cyclopropenecarboxylate esters and cyclopropenyl ketones to .alpha.-pyrones and of vinylcyclopropenes to phenols

Cho, Suk H.; Liebeskind, L. S.

doi:10.1021/jo00388a064

Cited by 111 publications

(43 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, Hoye suggested that formation of the furan may occur via rhodacyclobutene 40, which is more likely to be directly produced from zwitterionic intermediate 42, rather than via the oxidative addition of metal into the C−C bond of the highly strained bicyclic cyclopropene 43 (Scheme 10) [30]. A similar mechanism of cyclopropene isomerization was discussed by Liebeskind [31]. According to his rationale, initial electrophilic attack by the Rh complex on the double bond of cyclopropene 46 affords the best stabilized tertiary cyclopropyl cation 47 [32], followed by ring expansion to provide metallocyclobutene 48, which exists in equilibrium with its regioisomer 50.…”

Section: Methodsmentioning

confidence: 79%

“…This equilibrium is significantly shifted to the left when R 3 = H, since the 1,3-disubstituted metallocyclobutene species is more stable than its 1,2-disubstituted analog. Next, both regioisomers 48 and 50 either rapidly cycloisomerize into corresponding furans 51 and 53 or undergo CO insertion, ultimately producing the corresponding 2H-pyranones 52 and 54, respectively (Scheme 11) [31]. Padwa employed an analogous rationale to explain the predominant formation of 2,5-disubstituted furans 53 (R 3 = H) upon treatment of 3-acylcyclopropenes with catalytic Rh(I) complexes -in contrast to the formation of 2,4-disubstituted products 51 (R 3 = H), typically observed in Rh(II)-catalyzed reactions [20].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Rearrangements of cyclopropenes into five-membered aromatic heterocycles: mechanistic aspect

Rubin

Ryabchuk

2012

Chem Heterocycl Comp

View full text Add to dashboard Cite

This review covers rearrangements of cyclopropenes into aromatic five-membered heterocyclic compounds, namely furans and pyrroles; accompanied by small ring cleavage proceeding in the presence of catalytic amounts of transition metals, Lewis acids, or under UV irradiation. Due to significant strain in the small ring, cyclopropenes are characterized by increased energy and a conformationally constrained hydrocarbon skeleton, which chiefly defines their unusually high reactivity and selectivity in reactions atypical for other unsaturated compounds. The increased electronic density of the π-system of its strained double bond makes cyclopropene a very attractive substrate for π-philic transition metals [1]]. In turn, this opens avenues for extremely rich coordination chemistry for different types of catalytic rearrangements, as well as for addition and cycloaddition reactions. The important role of small cycles in the photochemistry of furans was first demonstrated in reports by Srinivason [2, 3] and van Tamelen [4,5], who discovered that the photo-rearrangement of 2-methylfurans 1 into 3-methylfurans 2 proceeds via a valent rearrangement forming 3-acylcyclopropene intermediate 3 (Scheme 1). In addition, in the reaction of furan 1а a competing photodecarbonylation leading to product 4 was detected, which confirmed the formation of intermediate 3-formylcyclopropene 3а (Scheme 1).Scheme 1

show abstract

Section: Methodsmentioning

confidence: 79%

Section: Methodsmentioning

confidence: 99%

Rearrangements of cyclopropenes into five-membered aromatic heterocycles: mechanistic aspect

Rubin

Ryabchuk

2012

Chem Heterocycl Comp

View full text Add to dashboard Cite

show abstract

“…Interest in metal-bound vinylketenes as reaction intermediates [ 1013 – 1015 ] led to facile preparation of (vinylketene)tricarbonyliron(O) complexes [ 1016 ], and the synthesis of (vinylketeneimine)tricarbonyliron(O) complexes [ 1017 ].…”

Section: Addendamentioning

confidence: 99%

New chemical and stereochemical applications of organoiron complexes

Fatiadi

1991

J. RES. NATL. INST. STAN.

View full text Add to dashboard Cite

The objective of this review is to provide a current overview of the rapidly developing chemistry of organometallic complexes and particularly organoiron complexes useful in asymmetric and stereoselective reactions. Also covered are stereoselective reactions of α, β-unsaturated acyl ligands bound to the chiral auxiliary [(η5-C5H5) Fe(CO)(PPh3)] and new applications of organoiron complexes in the synthesis of natural products. The mechanistic aspects and stabilizing effects of the Fe(CO)3 group for alkenes or conjugated dienes are discussed. A brief summary of recent work on the special role of iron in biological reactions is also included.

show abstract

“…[11][12][13][14][15] and the frequent postulation of metalbound vinylketenes as reaction intermediates (ref. [16][17][18], we decided that a study of the reactivity of our (viny1ketene)tricarbonyliron complexes would prove interesting and rewarding. Before we embarked on these investigations however, we spent some time delineating a reaction pathway for the vinylketone-vinylketene conversion.…”

Section: Synthesis Of (Vinylketene) Tricarbonyliron Complexesmentioning

confidence: 99%

Transition metal-stabilised vinylketenes

Hill¹,

Richards²,

Thomas³

1990

Pure and Applied Chemistry

View full text Add to dashboard Cite

-(Vinylketene)tricarbonyliron complexes are synthesised from readily-available (vinylketone)tricarbonyliron complexes. They react with isonitriles to give (vinylketenimine)tricarbonyliron complexes and with nucleophiles at C-1 to give p,yunsaturated carbonyl derivatives. In contrast (vinylketenimine)tricarbnyliron complexes react with nucleophiles at C-2 to give P,y-unsaturated carbonyl derivatives containing an a quaternary centre. This approach has been used to generate homochiral quaternary centres.

show abstract

Practical organic synthesis with strained ring molecules. Rhodium catalyzed carbonylation of cyclopropenecarboxylate esters and cyclopropenyl ketones to .alpha.-pyrones and of vinylcyclopropenes to phenols

Cited by 111 publications

References 0 publications

Rearrangements of cyclopropenes into five-membered aromatic heterocycles: mechanistic aspect

Rearrangements of cyclopropenes into five-membered aromatic heterocycles: mechanistic aspect

New chemical and stereochemical applications of organoiron complexes

Transition metal-stabilised vinylketenes

Contact Info

Product

Resources

About