82202-16-2Relevant articles and documents
Intramolecular nucleophilic acyl substitution reactions mediated by XTi(O-i-Pr)3 (X = Cl, O-i-Pr)/2i-PrMgBr reagent. Efficient synthesis of functionalized organotitanium compounds from unsaturated compounds
Okamoto,Kasatkin,Zubaidha,Sato
, p. 2208 - 2216 (2007/10/03)
Treatment of acetylenic or olefinic carbonates and esters with a low-valent titanium reagent diisopropoxy(η2-propene)titanium (1), readily generated by the reaction of Ti(O-i-Pr)4 or ClTi(O-i-Pr)3 with 2i-PtMgX, resulted in an intramolecular nucleophilic acyl substitution (INAS) reaction to afford organotitanium compounds having a carbonyl functional group, in good to excellent yields. Thus, the treatment of alkyl alkynyl carbonates 2 or alkyl alkenyl carbonates 4 with 1 gave organotitanium compounds having a lactone and/or ester group. Similarly, alkyl alkynoates 10 or alkynyl esters 14 of carboxylic acids reacted with 1 to give organotitanium compounds having a cyclic or acyclic ketone group, respectively. Thus, the reaction provides, after hydrolysis, five- or six-membered α-alkylidene lactones and/or α,β-unsaturated esters from 2, γ-butyrolactone derivatives from 4, five- or six-membered α-alkylidene cyclic ketones from 10, and acyclic α,β-unsaturated ketones 15 from 14. In all cases, the yields are excellent and the generation of the organotitanium compounds was confirmed by deuterolysis. The organotitaniums 6 and 11c reacted smoothly with iodine to afford 2-(iodomethyl)-4-butanolide (9) and α-[iodo(trimethylsilyl)methylidene]cyclopentanone, respectively. The organotitanium compounds obtained here also reacted with aldehydes to give the corresponding adducts, thus opening up a new access to substituted α,β-butenolides from 2, to γ-butyrolactones from 4, and to the corresponding tetrasubstituted furan from 10 and 14.
Cycloelimination of β-Silylethyl Sulphoxides: Alkene, Alkyne, and Vinylsilane-forming Reactions
Fleming, Ian,Goldhill, Jon,Perry, David A.
, p. 1563 - 1570 (2007/10/02)
The cycloelimination (1)->(3) of trimethylsilyl sulphenate from a β-silylethyl sulphoxide is slightly faster than the corresponding cycloelimination (2)->(3) of sulphenic acid itself.The former type of reaction can be used to form acetylenes (
THE SYNTHESIS OF αβ-UNSATURATED KETONES FROM β-SILYLENONES AND β-SILYLYNONES
Fleming, Ian,Perry, David A.
, p. 4027 - 4034 (2007/10/02)
Conjugate addition, followed by alkylation, bromination and desilyl-bromination make the β-silylketone (4) an a3d2-synthon (5) and the β-silylynone (6) a 2a3d2-synthon (7).
