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Published on: August 22, 2018
Domino Route toward 1,5-Diazocines from 1,4,5,6-Tetrahydropyrimidines and Propiolic Acid Derivatives via a Ring
Nikita E Golantsov1, Sergei I Vakulenko1, Anastasia S Smirnova1
1Organic Chemistry Department, Science Faculty, Peoples' Friendship University of Russia Named After Patrice Lumumba (RUDN University), 6 Mi-klukho-Maklaya St., Moscow117198, Russia.
Abstract:
1,4,5,6-Tetrahydropyrimidines react with propiolic acid esters or amides to form pseudo-three-component adducts containing a 1,5-enyne fragment. Under the action of acid or acid chlorides, these adducts undergo a domino transformation initiated by an aza-Claisen rearrangement, leading to ring expansion from a six- to an eight-membered cycle, accompanied by formal enyne metathesis. The process represents a one-pot procedure for the synthesis of 1,5-diazocines from 1,4,5,6-tetrahydropyrimidines and propiolic acid derivatives under ambient conditions, affording the products in 39-80% overall yields.
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The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
