Stereoselective Synthesis of (-)-α-Conhydrine and Its Pyrrolidine Analogue
作者:Guang Ri Dong、Seungmin Hong、Seung In Kim、In Su Kim、Young Hoon Jung
DOI:10.1002/ejoc.201200489
日期:2012.8
The stereoselective synthesis of (–)-α-conhydrine and its pyrrolidine analogue was achieved from readily available D-erythronolactone. The key step of this synthesis includes a highlyregioselective and diastereoselective addition of chlorosulfonylisocyanate to 1,2-anti-dibenzyl ether to afford the 1,2-anti-amino alcohol.
Enantioselective synthesis of (−)-α-conhydrine via cyclic sulfate methodology
作者:SubbaRao V. Kandula、Pradeep Kumar
DOI:10.1016/s0040-4039(03)00031-5
日期:2003.2
An asymmetric synthesis of (−)-α-conhydrine is described using the Sharpless asymmetric dihydroxylation and the regiospecific nucleophilic opening of a cyclic sulfate as the key steps.
The short and efficient synthesis of (−)-α-conhydrine was accomplished with 41% overall yield in seven steps and high diastereo- and enantioselectivity. The anti-stereochemistry of the two stereogenic centers has been confirmed by the single-crystal X-ray analysis of an intermediate.
The first asymmetric synthesis of the conium alkaloid (-)-alpha-conhydrine is reported. Starting from a protected glycol aldehyde hydrazone as chiral precusor, a short route based on our alpha-alkylation/1,2-addition methodology has been developed. After cleavage of the auxiliary and simultaneous deprotection, the concluding ring closure is accomplished under reductive amination conditions. The title compound is obtained in moderate overall yield and in excellent diastereo- and enantiomeric excess (d.e., e.e. >96%). Single-crystal X-ray crystallography as well as H-1 NMR NOE experiments confirm the expected relative and absolute (2R,7S)-configuration of the product. (C) 2002 Elsevier Science Ltd. All rights reserved.
A straightforward synthesis of conhydrine by hetero Diels–Alder strategy mediated by microwaves
Synthesis of optically active conhydrines has been achieved by hetero Diels-Alder cycloaddition assisted by microwaves. (C) 2009 Elsevier Ltd. All rights reserved.