Efficient 1,2-Addition of Aryl- and Alkenylboronic Acids to Aldehydes Catalyzed by the Palladium/Thioether−Imidazolinium Chloride System
摘要:
[GRAPHICS]The high level of catalyst performance was attainable in the palladium-catalyzed 1,2-addition of aryl-, heteroaryl-, and alkenylboronic acids to aromatic, heteroaromatic, and aliphatic aldehydes using thioether-imidazolinium chloride L5 as a heterobidentate carbene ligand precursor.
An enantioselective oxa-Piancatelli reaction was established for the first time using a chiral vanadium(V) catalyst. The dual Brønsted and Lewis acid properties of the vanadium catalyst afforded 4-hydroxycyclopent-2-enone derivatives in up to 90% yields and with 93 : 7 enantiomeric ratios, as well as >20 : 1 diastereomeric ratios.
Efficient synthesis of 4-hydroxycyclopentenones: dysprosium(III) triflate catalyzed Piancatelli rearrangement
作者:David Fisher、Leoni I. Palmer、Jonathan E. Cook、Jessica E. Davis、Javier Read de Alaniz
DOI:10.1016/j.tet.2014.03.007
日期:2014.7
4-Hydroxycyclopentenones represent a privileged scaffold in chemical synthesis. A dysprosium(III) trifluoromethanesulfonate catalyzed rearrangement of furylcarbinols to 4-hydroxycyclopentenones via a 4π electrocyclization has been developed. The catalytic Piancatelli rearrangement affords a single trans-diastereomer from both aryl and alkyl substituted furylcarbinols.
A chiral N,N′-dioxide/cobalt(II) complex catalyzed highly diastereoselective and enantioselective tandem aza-Piancatelli rearrangement/intramolecular Diels–Alderreaction has been disclosed. Various valuable hexahydro-2a,5-epoxycyclopenta[cd]isoindoles bearing six contiguous stereocenters have been obtained in good yields with excellent diastereo- and enantio-selectivities from a wide range of both
已公开了一种手性N,N'-二氧化物/钴(II)配合物,催化高度非对映选择性和对映选择性的串联氮杂-Piancatelli重排/分子内狄尔斯-阿尔德反应。从各种现成的2-呋喃基甲醇和N-(呋喃-2)中,以良好的收率获得了具有六个非连续立体中心的高收率的各种有价值的六氢-2 a,5-环氧环戊基[ cd ]异吲哚,并具有六个连续的立体中心。-基甲基)苯胺。
An efficient organocatalyticenantioselective aza‐Piancatelli rearrangement is disclosed. The powerful process provides rapid access to valuable chiral 4‐amino‐2‐cyclopentenone building blocks from readily available 2‐furfurylcarbinols with excellent chemo‐, enantio‐, and diastereoselectivities under mild reaction conditions.
cascade cyclization has been developed to streamline the synthesis of valuable multifunctionalized enantioenriched cyclopenta[f]pyrrolo[1,2-d][1,4]diazepinones bearing three contiguous stereocenters in high yields with excellent control of stereochemistry from a wide range of both readily available 2-furylcarbinols and (1H-pyrrol-1-yl)anilines, which represents the first asymmetric intramolecular conjugate
已经开发了手性布朗斯台德酸催化的高对映和非对映选择性级联环化反应,以简化合成有价值的多官能化对映体富集的环戊二烯[ f ]吡咯并[1,2- d ] [1,4]二氮杂吡啶酮的方法,该化合物高产率地具有三个连续的立体中心,且具有优异的收率。广泛地使用2-呋喃基甲醇和(1 H-吡咯-1-基)苯胺来控制立体化学,这代表了α,β-不饱和环酮与惰性N-取代吡咯的首次不对称分子内共轭加成作为第一个对映选择性氮杂-piancatelli重排/ Friedel-Crafts烷基化级联反应。