Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Synfacts mbr+ gati+ mmr+ juillet 2012


Published on

  • Be the first to comment

  • Be the first to like this

Synfacts mbr+ gati+ mmr+ juillet 2012

  1. 1. Ca t e g o r y W. GATI, M. M. RAMMAH, M. B. RAMMAH, F. COUTY, G. EVANO* (UNIVERSITÉ DE Metal-Mediated Synthesis VE R S A I L L E S S A I N T - Q U E N T I N E N YV E L I N E S , F R A N C E ; U N I V E R S I T É D E M O N A S T I R, Ke y w o rd s TU N I S I A ; U N I V E R S I T É L I B R E D E B R U X E L L E S , B E L G I U M ) De Novo Synthesis of 1,4-Dihydropyridines and Pyridines J. Am. Chem. Soc. 2012, 134, 9078–9081. pyridines 1,4-dihydropyridines N-allyl ynamides Synthesis of 1,4-Dihydropyridines and Pyridines out of N-Allyl Ynamides lithium Boc R1 Boc 1. s-BuLi (1.2 equiv) TMEDA (1.1 equiv) THF, –78 °C, 1 h N R1 2. NH4Cl (sat.) R2 1. s-BuLi (1.2 equiv) TMEDA (1.1 equiv) THF, –78 °C, 1 h N R1 2. o-chloranil (1 equiv) AcOH –78 to 25 °C, 30 min R2 R3 R3 N (1 equiv) quantitative R2 R3 up to 96% yield R = alkyl, (substituted) aryl, styryl R2 = H, Me R3 = H, Me, Ph Selected examples: N N H H t-Bu H Ph H MeO 81% yield N Ph H Ph 81% yield N H Ph 79% yield F 79% yield N t-Bu N H H H 96% yield H 84% yield N H H H 82% yield N Cl N 93% yield Ph H 93% yield Significance: An efficient, general, simple and Comment: The broad availability of the starting modular preparation of 1,4-dihydropyridines and pyridines has been disclosed. The formation of the products proceeds via a lithiation–isomerization– carbolithiation sequence and provides the (dihydro)pyridines in high yields. N-allyl ynamides implies that an extensive range of substituents can be selectively incorporated on the (dihydro)pyridine ring. According to the authors, this is the first example of an anionic 6endo-dig cyclization. SYNFACTS Contributors: Paul Knochel, Christoph Sämann Synfacts 1012, 8(8), 0900 Published online: 19.07.20121861-19581861-194X 2 8 0 DOI: 10.1055/s-0032-1316638; Reg-No.: P09012SF ©oialr Geteo ehV Nue TSk get rw ·gg m Y r a 900 2012 © THIEME STUTTGART • NEW YORK Downloaded by: Harvard University Library. Copyrighted material. 1