934-42-9Relevant articles and documents
Strictly regiocontrolled α-monosubstitution of cyclic carbonyl compounds with alkynyl and alkyl groups via Pd-catalyzed coupling of cyclic α-iodoenones with organozincs
Negishi, Ei-Ichi,Tan, Ze,Liou, Show-Yee,Liao, Baiqiao
, p. 10197 - 10207 (2007/10/03)
The conditions for the Pd-catalyzed cross coupling of cyclic α-iodoenones, such as 2-iodo-2-cyclohexenone, with alkynylzincs have been optimized. The use of tris(o-furyl)phosphine (TFP) as a ligand and DMF as a solvent has led to the formation of α-alkynylenones in excellent yields. This optimized procedure has been applied to the synthesis of (±)-harveynone and (±)-tricholomenyn A in high yields. Investigation of related α-alkylation reactions using alkylzincs has revealed the following. Methylzinc and primary alkylzinc derivatives readily undergo Pd-catalyzed cross coupling with α-iodoenones. Although (s-Bu)2Zn also undergoes Pd-catalyzed cross coupling, only the n-Bu-substituted products were obtained, α-Benzylation and α-homobenzylation can proceed satisfactorily, whereas allylzinc and propargylzinc derivatives undergo only addition to the carbonyl group. Although some promising results have been obtained in α-homoallylation and α-homopropargylation, these reactions need to be further improved. (C) 2000 Elsevier Science Ltd.
Consecutive 6-endo trigonal cyclisations from polyene acyl radical intermediates leading to decalone and perhydrophenanthrone ring constructions
Chen, Ligong,Gill, G. Bryon,Pattenden, Gerald,Simonian, Houri
, p. 31 - 44 (2007/10/03)
A range of substituted Se-phenyl 5,9-dieneselenoates, viz. 15a, 25, 26, 27, 42 and 52, have been synthesised and their reactions with Bu3SnH-AIBN investigated.The diene esters 15a, 42 and 52 are shown to lead to decalone and to perhydrophenanthrone derivatives, viz. 19, 43 and 53, respectively, via consecutive 6-endo trig modes of cyclisations starting from the corresponding 5,9-diene acyl radical intermediates.By contrast, the 5,9-dienoates 25 and 27 lacking alkyl substitution at C-9 instead underwent cyclisation to the indanones 36 and 37, respectively, and the 6-methyl substituted analogue 26 produced only the cyclopentanone 38 on treatment with Bu3SnH-AIBN.
An Organozinc Aid in Alkylation and Acylation of Lithium Enolates
Morita, Yasushi,Suzuki, Masaaki,Noyori, Ryoji
, p. 1785 - 1787 (2007/10/02)
The presence of dimethylzinc in the reaction of lithium enolates and electrophiles effectively suppresses undesired α-proton exchange reaction and enhances the efficiency of enolate alkylation and acylation.