Generation of dienone and trienone dianion derivatives
作者:Dieter Seebach、Manat Pohmakotr
DOI:10.1016/s0040-4020(01)93280-6
日期:——
the dianions2, LUMO filled π-systems, from hydrogenated precursors, see schemes 1 and 2. The preparation of the allylated ketones 3a–d, of the acid derivatives 3e–h, 9, 10, 12 as well as of the dienones 11 is described. Their double deprotonation (→14, 18, 26, 30, 33, 36, and 40) is carried out by sequential treatment with potassium hydride and s-butyllithium/tetramethylethylene diamine (TMEDA) in
A new, wide ranging, synthetically powerful, catalytic tandem cyclisation-anion capture process is proposed which depends on the rate of cyclisation of an organopalladium specifies (RPdX) onto a proximate alkene or diene being significantly faster than anion exchange and reductive elimination in the sequence RPdX → RPdY → RY + Pd(0). The catalytic cyclisation - anion capture sequence is illustrated
Benzyne 1,2,4-Trisubstitution and Dearomative 1,2,4-Trifunctionalization
作者:Jiarong Shi、Lianggui Li、Chunhui Shan、Zhonghong Chen、Liang Dai、Min Tan、Yu Lan、Yang Li
DOI:10.1021/jacs.1c04389
日期:2021.7.21
4-trifunctionalization of benzyne have been accomplished from sulfoxides bearing a penta-2,4-dien-1-yl moiety. These cascade transformations proceed through a benzyne insertion into the S═O bond and an uncommon regiospecific anionic [4,5]-sigmatropic rearrangement, furnishing a C–O, C–S, and C–C bond on the C1-, C2-, and C4-position of a benzene ring, respectively. This study showcases new cascade benzyne reaction
Free Radical Cyclizations of Trienes with Tris(Trimethylsilyl)Silane
作者:Nora E. Restrepo-Sánchez、Fernando J. Gómez、Luz M. Jaramillo-Gómez、Tomas Hudlioky
DOI:10.1080/00397919908086447
日期:1999.8
Abstract The intramolecular trapping of a stabilized intermediate allylic radical generated by the addition of tris(trimethylsilyl)silyl (sisyl) radical to a conjugated system was performed. The observed low stereoselectivity suggests thermodynamic rather than kinetic control in this cyclization process.
Chiral Ruthenium Lewis Acid Catalyzed Intramolecular Diels−Alder Reactions
作者:Sirinporn Thamapipol、Gérald Bernardinelli、Céline Besnard、E. Peter Kündig
DOI:10.1021/ol1019103
日期:2010.12.17
Single point binding ruthenium Lewis acid catalysts [Ru(acetone)(S,S)-BIPHOP-F)Cp][SbF6] ((S,S)-1b) and [Ru(acetone)(S,S)-BIPHOP-F)(indenyl)][SbF6] ((S,S)-1c) efficiently catalyze intramolecularDiels−Alder (IMDA) reactions under mild conditions to afford the endo cycloaddition products as the major product in excellent yields with high diastereo- and enantioselectivities.