Issue 4, 2015

Synthesis of (−)-mesembrine using the quaternary carbon-constructing allylic substitution

Abstract

Synthesis of (−)-mesembrine was studied by using the allylic substitution for construction of quaternary carbons. The required allylic picolinate 6 (R = TBS) with the three substituents on the olefin was synthesized by hydromagnesiation of propargylic alcohol (S)-13 followed by iodination, Pd-catalyzed coupling of the resulting vinyl iodide (S)-14 with CH2[double bond, length as m-dash]CH(CH2)2MgBr and esterification with PyCO2H. The substitution proceeded stereo- and regioselectively to afford SN2′ product 9, which was transformed to keto aldehyde 29 by substitution with NsMeNH, Wacker oxidation and ozonolysis. Finally, aldol reaction and subsequent de-nosylation afforded the title compound. During the synthesis, the coupling of the vinyl iodide with alkylmetals was investigated under the Negishi conditions.

Graphical abstract: Synthesis of (−)-mesembrine using the quaternary carbon-constructing allylic substitution

Supplementary files

Article information

Article type
Research Article
Submitted
29 ဒီ 2014
Accepted
31 ဇန် 2015
First published
03 ဖေ 2015

Org. Chem. Front., 2015,2, 328-335

Synthesis of (−)-mesembrine using the quaternary carbon-constructing allylic substitution

T. Ozaki and Y. Kobayashi, Org. Chem. Front., 2015, 2, 328 DOI: 10.1039/C4QO00353E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements