Asymmetric synthesis of spiro[chroman-3,3′-pyrazol] scaffolds with an all-carbon quaternary stereocenter via a oxa-Michael–Michael cascade strategy with bifunctional amine-thiourea organocatalysts

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91108-91113 ◽  
Author(s):  
Weiping Zheng ◽  
Jiayong Zhang ◽  
Shuang Liu ◽  
Chengbin Yu ◽  
Zhiwei Miao
Keyword(s):  
Asymmetric Synthesis ◽  
Cascade Reaction ◽  
Quaternary Stereocenter

The chiral spiro[chroman-3,3′-pyrazol] derivatives have been synthesized through a catalytic oxa-Michael–Michael cascade reaction of 2-hydroxynitrostyrenes with 4-alkenyl pyrazolin-3-ones in good yields with moderate to high stereoselectivities.

Asymmetric Synthesis of Indolines Bearing a Benzylic Quaternary Stereocenter through Intramolecular Arylcyanation of Alkenes

Synlett ◽  
2010 ◽  
Vol 2010 (11) ◽  
pp. 1709-1711 ◽  
Author(s):  
Yoshiaki Nakao ◽  
Tamejiro Hiyama ◽  
Jen-Chieh Hsieh ◽  
Shiro Ebata
Keyword(s):  
Asymmetric Synthesis ◽  
Quaternary Stereocenter

Asymmetric synthesis of highly functionalized spirothiazolidinone tetrahydroquinolines via a squaramide-catalyzed cascade reaction

2018 ◽  
Vol 16 (48) ◽  
pp. 9390-9401 ◽  
Author(s):  
Yong-Xing Song ◽  
Da-Ming Du
Keyword(s):  
Asymmetric Synthesis ◽  
Michael Addition ◽  
Addition Reaction ◽  
Cascade Reaction ◽  
Michael Addition Reaction

A bifunctional squaramide-catalyzed asymmetric cascade aza-Michael/Michael addition reaction for the synthesis of chiral spirothiazolidinone tetrahydroquinolines with three contiguous stereocenters has been developed.

Asymmetric Construction of Halogenated Cyclic Quaternary Carbon Center through Enolate Activation of Aldehydes

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2601-2607 ◽  
Author(s):  
Jun-Long Li ◽  
Qing-Zhu Li ◽  
Yue Liu ◽  
Hai-Jun Leng
Keyword(s):  
Asymmetric Synthesis ◽  
Synthetic Methods ◽  
Quaternary Carbon ◽  
Quaternary Stereocenter

The construction of a chiral halogenated cyclic quaternary carbon center through various catalytic strategies is an emerging hot topic in the field of asymmetric synthesis. Herein, we give a summary of recently developed synthetic methods for preparing such structures. In addition, a novel enolate activation mode of aldehydes is highlighted, which provides an elegant pathway to access enantiopure heterocycles featuring a halogenated quaternary stereocenter through organocatalytic [4+2] cycloaddition.

Asymmetric total synthesis of (−)-δ-lycorane

2017 ◽  
Vol 4 (6) ◽  
pp. 1149-1152 ◽  
Author(s):  
Junliang Wang ◽  
Jianneng Li ◽  
Xianwang Shen ◽  
Cong Dong ◽  
Jun Lin ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Cascade Reaction ◽  
Asymmetric Total Synthesis

A first asymmetric synthesis of (−)-δ-lycorane by using a chiral bifunctional squaramide-catalysed cascade reaction is reported.

Direct enantioselective Mannich reactions of α-azido cyclic ketones: asymmetric construction of chiral azides possessing an α-quaternary stereocenter

2020 ◽  
Vol 56 (1) ◽  
pp. 98-101 ◽  
Author(s):  
Xueqian Ye ◽  
Yongkai Pan ◽  
Xiaoyu Yang
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Cyclic Ketones ◽  
Mannich Reactions ◽  
Chiral Phosphoric Acid ◽  
Quaternary Stereocenter

Herein, we report the asymmetric synthesis of chiral azides possessing an α-quaternary stereocenter via chiral phosphoric acid catalysed direct enantioselective Mannich reactions of α-azido cyclic ketones with aldimines.

A Concise and Modular Three-Step Synthesis of (S)-Verapamil using an Enantioselective Rhodium-Catalyzed Allylic Alkylation Reaction

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2185-2189 ◽  
Author(s):  
P. Andrew Evans ◽  
Mai-Jan Tom ◽  
Ben W. H. Turnbull
Keyword(s):  
Calcium Channel ◽  
Asymmetric Synthesis ◽  
Channel Blocker ◽  
Alkylation Reaction ◽  
Allylic Alkylation ◽  
Efficient Synthesis ◽  
Terminal Olefin ◽  
Bioactive Agents ◽  
Quaternary Stereocenter ◽  
Modular Nature

A concise and modular asymmetric synthesis of the calcium channel blocker (S)-verapamil is described. This approach employs an enantioselective rhodium-catalyzed allylic alkylation reaction between an α-isopropyl-substituted benzylic nitrile and allyl benzoate to construct the challenging acyclic quaternary stereocenter. The terminal olefin then serves as a convenient synthetic handle for a hydroamination to introduce the phenethylamine moiety, furnishing (S)-verapamil in three steps and 55% overall yield, thus providing the most efficient synthesis of this important pharmaceutical reported to date. Furthermore, given the modular nature of the synthesis, it can be readily modified to prepare structurally related bioactive agents.

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