Stereoselective synthesis of the ABC ring system of norzoanthamine.
نویسندگان
چکیده
[reaction: see text] An efficient synthesis of enone 4, representing the ABC ring motif of norzoanthamine, is presented. The crucial C22 quaternary center was introduced via a stereoselective methylation of enone 8. The trans-anti-trans relative configuration of the ABC framework of 4 was installed via a sequence of reactions that included a hydroboration and a modified Robinson annulation.
منابع مشابه
Enantioselective synthesis of the ABC ring motif of norzoanthamine based on asymmetric Robinson annulation reactions.
An enantioselective strategy for the synthesis of tetracyclic motif 5, representing the northern fragment of norzoanthamine, is presented. Key to the strategy is the use of two asymmetric Robinson annulation reactions that produce the tricyclic ABC ring system with excellent stereoselectivity. Further functionalization at the periphery of the C ring produces compound 5 containing six contiguous...
متن کاملSTEREOSELECTIVE SYNTHESIS OF METHYL TETRA-0-METHYL a-AND P-D-GLUCO-AND MANNOPYRANOSIDES
Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-Bu...
متن کاملA Three-Component 1,3-Dipolar Cycloaddition Reaction of Azomethine Ylide for Synthesis of New Bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) Derivatives
The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...
متن کاملA Three-Component 1,3-Dipolar Cycloaddition Reaction of Azomethine Ylide for Synthesis of New Bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) Derivatives
The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...
متن کاملMicrowave-Assisted Synthesis of Novel Functionalized Ketenimines and Azadienes via a Solvent-Free Reaction of Isatoic Anhydride, Alkyl-Isocyanides and Dialkyl Acetylenedicarboxylates
Ketenimines and azadienes are transient intermediates in organic chemistry especially in elimination-addition processes and in the formation of heterocyclic systems. These compounds play a considerable role as intermediates in the synthesis of heterocyclic ring systems. In this present research synthesis of novel ketenimines and azadienes via multicomponent reactions (MCRs...
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 letters
دوره 6 6 شماره
صفحات -
تاریخ انتشار 2004