Synthesis of Functionalized 1-Alkenylboronates via Hydroboration-Dealkylation of Alkynes with Diisopinocampheylborane
摘要:
Hydroborations of propargyl chloride, ethyl propiolate, 3-trimethyl-silyloxy-1-butyne, 1,1-diethoxy-2-propyne, 1-iodo- and 1-bromo-1-hexyne, and 1-bromo-3-chloro-1-propyne with diisopinocampheylborane 1, followed by dealkylation of the isopinocampheyl groups with acetaldehyde provide the corresponding 1-alkenylboronates in high yields with high regioselectivity.
Stereoselective Synthesis of (+)-Goniodiol, (+)-Goniotriol, (-)-Goniofupyrone, and (+)-Altholactone Using a Catalytic Asymmetric Hetero-Diels-Alder/Allylboration Approach
The stereoselective totalsynthesis of several members of the styryllactone family was achieved efficiently from common intermediate 8, prepared by a catalytic asymmetric inverse-electron-demand hetero-Diels–Alder/allylboration sequence. The transformation of 8 into α,β-unsaturated lactone led to the preparation of (+)-goniodiol (1) in a reduced number of steps. The epoxidation reaction was used to
Catalytic Asymmetric Synthesis of a Potent Thiomarinol Antibiotic
作者:Xuri Gao、Dennis G. Hall
DOI:10.1021/ja042827p
日期:2005.2.1
and Gram-negative activity. The first total synthesis of a member of the thiomarinol class of marine antibiotics was achieved in a remarkable global yield of 22% (from 3-boronoacrolein pinacolate). The highlight of this synthesis is the efficient catalytic enantio-, regio-, E/Z-, and diastereoselective three-component inverseelectrondemandDiels-Alder/allylboration sequence. This key operation provides
Synthesis and preliminary antibacterial evaluation of simplified thiomarinol analogs
作者:Olivier Marion、Xuri Gao、Sandra Marcus、Dennis G. Hall
DOI:10.1016/j.bmc.2008.01.001
日期:2009.2
derivatives was prepared by way of catalytic enantioselective inverseelectrondemand hetero [4 + 2] cycloaddition/allylboration tandem reaction. As a preliminary evaluation, these analogs were tested for antimicrobial activity using a standard disk diffusion assay. Whereas amide analogs were less active, the simple ester analogs 3 and 4 were demonstrated to be more active than thiomarinol H.
α-Hydroxyalkyl Heterocycles via Chiral Allylic Boronates: Pd-Catalyzed Borylation Leading to a Formal Enantioselective Isomerization of Allylic Ether and Amine
作者:Stéphanie Lessard、Feng Peng、Dennis G. Hall
DOI:10.1021/ja903946f
日期:2009.7.22
piperidinyl allylicboronates was achieved via a palladium-catalyzed borylation/isomerization reaction on the corresponding alkenyl triflates. The influence of the base and solvent was found to be crucial on the regio- and enantioselectivity of this reaction. The overall borylation process constitutes a successful example of formal asymmetric isomerization of allylic ether/amine. The resulting allylic boronate