Enantioselective Allylic Amination of Morita–Baylis–Hillman Carbonates Catalysed by Modified Cinchona Alkaloids

Abstract

An efficient procedure for the asymmetric allylic amination of Morita-Baylis-Hillman carbonates with cyclic imides catalysed by commercially available cinchona alkaloids is reported. It proves to be a facile protocol that affords α-methyl-

Chiral Bifunctional Thiourea–Phosphane Organocatalysts in Asymmetric Allylic Amination of Morita–Baylis–Hillman Acetates

“…We have further explored the transformation of the obtained products 3 in order to illustrate their synthetic versatility. For example, product 3j could be smoothly transformed into a synthetically more useful compound through [3+2] cycloaddition with chlorobenzaldoxime in dichloromethane (DCM) at 0 °C, affording the major diastereomeric product 4j in 84 % isolated yield with ee value retained (the total diastereomeric selectivity was 6:1) (Scheme ) 5e…”

“…In 2007, Hou and co‐workers used planar chiral [2,2]paracyclophane monophosphanes as catalysts to provide the allylic amination products in high regioselectivities and modest enantioselectivities (9–71 % ee s) 4. Moreover, thus far, Chen and co‐workers have used (DHQD) 2 AQN, (DHQD) 2 PHAL, (DHQD) 2 PYR, and β‐ICD in asymmetric substitutions of MBH carbonates to achieve C–Cbond,5a–5d C–N bond,5e–5f and C–O bond5g–5h formation in good yields along with high enantioselectivities. More recently, Wang and co‐workers also reported the construction of chiral allylic phosphane oxides by using cinchona alkaloids as catalysts through substitution of MBH carbonates in excellent yields along with high enantioselectivities 6.…”

Organocatalytic asymmetric allylic alkylation of sulfonylimidates with Morita-Baylis-Hillman carbonates

“…Our group have also reported that modified cinchona alkaloids can act as excellent organocatalysts for asymmetric allylic alkylation (AAA) reactions with MBH carbonates [23][24][25][26][27][28]. On the other hand, the deprotonation of α-position from a carbonyl compound and the subsequent nucleophilic addition of the formed enolate is a fundamental sequence of transformations in Scheme 1 Proposed allylic alkylation of sulfonylimidates with MBH carbonates catalyzed by tertiary amine.…”

Metal‐Free SN2′ Decarboxylative Rearrangement of β‐Keto Esters

“…[10] S N 2Ј reactions are also common reactions for intermolecular functional modifications of Morita-Baylis-Hillman adducts. [10,11] From a slightly different point of view, the transformation we envisaged could be related to a base-induced Carroll reaction, which is a variant of the Claisen rearrangement (Scheme 2).…”