Hydroboration–azide alkylation as efficient tandem reactions for the synthesis of chiral non racemic substituted pyrrolidines
摘要:
The synthesis of chiral non racemic substituted pyrrolidines from homoallylic alcohols is presented. These precursors are readily converted via the azides to the corresponding pyrrolidines using hydroboration-cycloalkylation tandem reactions as key steps. (C) 1998 Elsevier Science S.A. All rights reserved.
Enantioselective Multicomponent Condensation Reactions of Phenols, Aldehydes, and Boronates Catalyzed by Chiral Biphenols
作者:Keith S. Barbato、Yi Luan、Daniele Ramella、James S. Panek、Scott E. Schaus
DOI:10.1021/acs.orglett.5b02954
日期:2015.12.4
Chiral diols and biphenolscatalyze the multicomponent condensation reaction of phenols, aldehydes, and alkenyl or aryl boronates. The condensation products are formed in good yields and enantioselectivities. The reaction proceeds via an initial Friedel–Crafts alkylation of the aldehyde and phenol to yield an ortho-quinone methide that undergoes an enantioselectiveboronateaddition. A cyclization
Facile Synthesis of Iodonium Salts by Reaction of Organotrifluoroborates with <i>p</i>-Iodotoluene Difluoride
作者:Masanori Yoshida、Kanako Osafune、Shoji Hara
DOI:10.1055/s-2007-966031
日期:——
A simple and easy method for the synthesis of various iodonium salts was developed, and involves the reaction of potassium organotrifluoroborates with P-iodotoluene difluoride under mild conditions. The one-pot synthesis of a ( Z)-(2-fluoroalkenyl)iodo-nium salt from an alkynyltrifluoroborate was also carried out.
A stereoselective synthesis of γδ-unsaturated ketones possessing perfluoroalkyl groups by trifluoroborane etherate mediated 1,4-addition reaction of alkenyldiisopropoxyboranes to α,β-unsaturated ketones
作者:Ei-ichi Takada、Shoji Hara、Akira Suzuki
DOI:10.1016/s0040-4039(00)61600-3
日期:1993.10
A variety of γ,δ-unsaturated ketones (3,5, and 7) having perfluoroalkyl groups were prepared stereoselectively by the trifluoroborane etherate mediated 1,4-addition reaction of alkenyldiisopropoxyboranes (1) to α,β-unsaturatedketones substituted by perfluoroalkyl group (2,4, and 6). The undesired 1,2-addition of alkenyl groups or elimination of metal fluoride from the adducts could be avoided completely
Organoboranes. 56. Systematic study of the reactions of 1-alkenylboronic esters with representative organolithium and Grignard reagents to provide an efficient, selective synthesis of organyl-1-alkenylborinic esters
作者:Herbert C. Brown、Nagarajan Vasumathi、Navalkishore N. Joshi
DOI:10.1021/om00028a021
日期:1993.4
A selective reaction of the ''ate'' complexes formed with 1-alkenylboronic esters and organolithium or Grignard reagents, by treatment with either Bronsted or Lewis acids at -78-degrees-C to give the corresponding organylalkenylborinic esters, is explored in this study. This systematic, detailed study reveals that the nature of the alkoxy group on boron, the nature and the amount of the alkyllithium or Grignard reagent used, the solvent, the reaction temperature, and the nature and amount of the acid used all play significant roles in influencing both the yield and the selectivity achieved for the formation of the desired organylalkenylborinates. Optimized procedures for the syntheses of representative organylalkenylborinic esters in high yield are summarized.