The Grob/Eschenmoser fragmentation of cycloalkanones bearing β-electron withdrawing groups: a general strategy to acyclic synthetic intermediates.
نویسندگان
چکیده
Introduction of a β-electron withdrawing group to cycloalkanones allows facile C-C bond fragmentation. The reaction has been demonstrated with a large range of ring sizes, bearing various leaving and electron withdrawing groups, and using a variety of nitrogen and oxygen containing nucleophiles (>30 examples). The application of fragmentation products to the preparation of substituted γ-lactones has been demonstrated. Mechanistic studies are reported which are suggestive of a Grob/Eschenmoser type reaction.
منابع مشابه
P-Dodecylbenzenesulfonic acid (DBSA), a Brønsted acidSurfactant Catalyst for Synthesis of α, ά-bis(substituted benzylidene)cycloalkanones with Electron-Withdrawing Substituent in Aqueous Media
An array of aromatic aldehydes with electron withdrawing groupunderwent crossed-Aldol condensation with cycloalkanone in the presence of catalytic amounts of DBSA under aqueous media to afford the corresponding α, ά-bis(substituted-benzylidene) cycloalkanones in good yields. The electronic effects on aromatic aldehydes could be observed. The present method is operationally simple and use of wat...
متن کاملApplication of Chan-Lam cross coupling for the synthesis of N-heterocyclic carbene precursors bearing strong electron donating or withdrawing groups
Chan-Lam cross coupling allowed efficient synthesis of N,N'-disubstituted ortho-phenylene diamines bearing strong electron donating or withdrawing groups, such as nitro or methoxy groups, with moderate to high yields. These diamines can then be turned into N-heterocyclic carbene precursors after condensation with trimethyl orthoformate. The same strategy can also be utilized for the synthesis o...
متن کاملUnravelling the reaction mechanism of the reductive ring contraction of 1,2-pyridazines.
Substituted pyrroles may be synthesized from selected 1,2-pyridazines through a reductive ring contraction involving the addition of four electrons and four protons. Our density functional theory computations of this reaction mechanism show that the first reduction event must be preceded by the uptake of one proton by 1,2-pyridazine and that the reaction proceeds through a 2e(-)/3H(+)-bearing i...
متن کاملRadical cyclizations involving the evolution of nitrogen
The rsuiical cyclizations of N-aziridinyl imines and alkyl azides provided reliable methods for the formation of fiveand six-membered carbon-centered and nitrogen-centered radicals from acyclic precursors. NAziridinyl imino and azido groups were utilized as radical precursors as well as radical acceptors in radical cyclization. Furthermore, intramolecular addition of aminyl radicals to carbonyl...
متن کاملSynthesis and anti-tubercular activity of 6-Substtitutedaryl-4-Arylidene-4,5-dihydropyridazin-3(2H)-one derivatives against Mycobacterium tuberculosis
Pyridazine plays a significant role in pharmaceuticals particularly in the field of medicinal chemistry. Several 4-substituted-benzylidene-6-substituted-phenyl-dihydro-pyridazin-3(2H)-one derivatives (3a-q) were synthesized and evaluated for their antimicrobial activities with an aim to obtain promising antitubercular agents. In the first step, 6-aryl-tetrahydro-pyridazin-3-ones (2) were prepar...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Organic & biomolecular chemistry
دوره 9 3 شماره
صفحات -
تاریخ انتشار 2011