Stereochemical aspects of the intramolecular Diels-Alder reactions of deca-2,7,9-trienoate esters. 3. Thermal, Lewis acid catalyzed, and asymmetric cyclizations
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.
Liquid crystal control. A remarkable enhancement of both efficiency and diastereoselectivity of intramolecular thermal cycloadditions in smectic solvents
作者:Kenji Fukunaga、Takehisa Kunieda
DOI:10.1016/s0040-4039(99)01200-9
日期:1999.8
The uncatalyzed intramolecular [4+2]cycloaddition of 2E, 7E,9(E)-decatrienoates, conducted at 140 °C in a medium of smecticliquid cryctals proceeds with a remarkably high level of chemical efficiency and diastereselectivity, in contrast to the isotropic phase reactions which result in much lower yield and selectivity.