Organotin enolates

Pereyre, Michel; Quintard, Jean‐Paul; Rahm, Alain

doi:10.1016/b978-0-408-01435-9.50018-3

Cited by 109 publications

(128 citation statements)

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“…It is possible that the a,P-unsaturated ketone was reduced Triphenyltin hydride (TPTH) and tri-n-butyltin hydride first. However, as 25 and 26 were also isolated, this could (TBTH) reduce a,P-unsaturated ketones via a radical mechimply that radical formation occurred at C-5 from bromohanism (18,19). It was therefore of interest to determine ydrin 2 1 and at C-6 from bromohydrin 24, respectively, whether a radical-induced intramolecular cyclization (20) whilst the a,P-unsaturated ketone was still present.…”

Section: M+o-mentioning

confidence: 99%

The chemistry of 5β,6β-epoxy-4,4-dimethylcholest-1-en-3-one. Approaches to the synthesis of 1α,5α-cyclosteroids. Part II

Georghiou¹,

Ren²

1993

Can. J. Chem.

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. Can. J. Chem. 71, 364 (1993).Epoxidation of 4,4-dimethylcholesta-1,5-dien-3-one (9) with MCPBA gives a mixture of the corresponding epimeric 5a,6a and 5P,6P epoxides. The major product is the 5P,6P epimer 6, in contradiction to what has been reported by others. The unambiguous assignment of the structures of these epoxides is based upon NMR NOED experiments. The chemistry of the 5P,6P epoxide is described in the context of unsuccessful attempts at synthesizing the corresponding l a , 5 a cyclosteroids. Reductive methods using lithium -liquid ammonia, lithium-ethylamine, or tri-n-butyl-or triphenyltin-AIBN gave products in which the a,P-unsaturated carbonyl system and the epoxide were reduced. When 6 was treated with BF,.etherate a B-nor derivative 27 was formed, presumably via a pinacol-type rearrangement.PARIS E. GEORGHIOU et YI REN. Can. J. Chem. 71, 364 (1993). L'Cpoxydation de la 4,4-dimCthylcholesta-1,5-dikn-3-one (9) par 1'AMCPB conduit 5 un melange des Cpoxydes Cpimeres correspondants 5a,6a et 5P,6P. Contrairement a ce qui a Ct C rapport6 par d'autres, le produit majeur est 1'Cpimkre 5P,6P (6). L'attribution non-ambigue des structures de ces Cpoxydes est basCe sur des experiences de RMN <. On dCcrit la chimie de 1'Cpoxyde 5P,6P dans le contexte d'essais infructueux de synthkse des la,5a cyclostCroides correspondants. Les reductions 5 l'aide de lithium -ammoniac liquide, de lithium-kthylamine ou des tri-n-butyl-ou triphCnylCtain-AIBN conduisent a des produits dans lesquels le systkme carbonyle a,p-insaturC et l'kpoxyde sont rCduits. Le traitement du produit 6 par du BF,.ether conduit a la formaton du derive B-nor 27, probablement par un rkarrangement de type pinacolique.[Traduit par la rCdaction]Introduction ~yclocholestan-7-one (3) via lithium -liquid ammonia The la,5a cyclocholesterols are relatively rare. Laing and reduction of cholest-5-ene-l,7-dione. More recently we Sykes (1, 2) reported the synthesis of la,5a-~yclochol~~t-2-~u~~e e d e d in synthesizing 4,4-dimethyl-la,5a-cyclochoene (I), and ~~-a c e t o x y -~~,~~-c y c~o c~o~e s t a n -6~o n e

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Section: M+o-mentioning

confidence: 99%

The chemistry of 5β,6β-epoxy-4,4-dimethylcholest-1-en-3-one. Approaches to the synthesis of 1α,5α-cyclosteroids. Part II

Georghiou¹,

Ren²

1993

Can. J. Chem.

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“…Organostannanes are organometallic reagents widely used for organic synthesis. 1 They are easy to handle because of their inertness towards oxygen and moisture, while the organostannanes are reactive with various electrophiles in the presence of appropriate activators. A typical example is the palladium-catalysed cross-coupling reaction (Stille coupling).…”

Section: Introductionmentioning

confidence: 99%

Addition of arylstannanes to alkynes givingortho-alkenylarylstannanes catalysed cooperatively by a rhodium complex and zinc chloride

2018

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“…Consequently, benzylated sugars find wide synthetic application as glycosylating reagents, chiral synthons and pharmaceuticalintermediate 5,6 . Carbohydrate stannylene acetals have proven to be useful intermediates in the regioselective synthesis of carbohydrate derivatives [7][8][9][10] , 1,6-dibutylstannylene acetals are reactive intermediates that have been treated with acylating and alkylating agents to provide mono-substituented derivatives of diols or polyols with high regioselectivity 11,12 . However for regioselective substitution of methyl α-D-glucoside, the substitution position on pyranoside cycle often varied with detailed condition.…”

Section: Introductionmentioning

confidence: 99%