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.
Enantio- and Diastereoselective Synthesis of Hydroxy Bis(boronates) via Cu-Catalyzed Tandem Borylation/1,2-Addition
作者:Jacob C. Green、Matthew V. Joannou、Stephanie A. Murray、Joseph M. Zanghi、Simon J. Meek
DOI:10.1021/acscatal.7b01123
日期:2017.7.7
Catalytic enantioselective synthesis of 1-hydroxy-2,3-bisboronate esters through multicomponent borylation/1,2-addition is reported. Catalyst and substrates are readily available, form both a C–B and C–C bond, and generate up to three contiguous stereocenters. The reaction is tolerant of aryl, vinyl, and alkyl aldehydes and ketones in up to 95% yield, >20:1 dr, and 99:1 er. Intramolecular additions
Straightforward chemoselective access to unsymmetrical dithioacetals through a thiosulfonate homologation-nucleophilic substitution sequence
作者:Laura Ielo、Veronica Pillari、Natalie Gajic、Wolfgang Holzer、Vittorio Pace
DOI:10.1039/d0cc04896h
日期:——
presented for the preparation of rare unsymmetrical dithioacetals. The judicious selection of thiosulfonates as convenient sulfur electrophilic sources – upon the homologation event conducted on an intermediate α-halothioether – guarantees the release of the non-reactive sulfonate group, thus enabling the subsequent nucleophilic displacement with an external added thiol [(hetero)aromatic and/or aliphatic]
Cascade Reactions: Catalytic Synthesis of Functionalized 1,3-Dihydroisobenzofuran and Tetrahydrofuran Derivatives by Sequential Nucleophilic Ring Opening-Heterocyclization- Oxidative Carbonylation of Alkynyloxiranes
作者:Nicola Della Ca'、Fabio Campanini、Bartolo Gabriele、Giuseppe Salerno、Chiara Massera、Mirco Costa
DOI:10.1002/adsc.200900436
日期:2009.10
Differently substituted alkynyloxiranes were efficiently converted into functionalized 1,3-dihydroisobenzofurans and tetrahydrofuran derivatives in fair to good yields by a new cascade reaction, consisting of a sequential nucleophilic ring opening–heterocyclization–oxidative carbonylation process. Reactions were carried out at 80–100 °C and under a 3:1 mixture of carbon monoxide and air (total pressure=32–42 atm
Ni-catalyzed 1,2-benzylboration of 1,2-disubstituted unactivated alkenes
作者:Seewon Joung、Allison M. Bergmann、M. Kevin Brown
DOI:10.1039/c9sc04199k
日期:——
Nickel-catalyzed 1,2-carboboration of alkenes is emerging as a useful method for chemical synthesis. Prior studies have been limited to only the incorporation of aryl groups. In this manuscript, a method for the 1,2-benzylboration of unactivated alkenes is presented. The reaction combines readily available alkenes, diboron reagents and benzylchlorides to generate synthetically versatile products with
Synthesis of Enantioenriched Tertiary Boronic Esters by the Lithiation/Borylation of Secondary Alkyl Benzoates
作者:Alexander P. Pulis、Daniel J. Blair、Eva Torres、Varinder K. Aggarwal
DOI:10.1021/ja409100y
日期:2013.10.30
range of neopentyl boronic esters which, after 1,2-metalate rearrangement and oxidation, gave a range of tertiaryalcohols in high yield and universally high er. Further functional group transformations of the tertiary boronic esters were demonstrated (conversion to quaternary centers, C-tertiary amines) together with application of the methodology to the synthesis of the simplest unbranched hydrocarbon