Year: 2016
Type: article
Abstract: The hexahydropyrroloindole (HPI) structure-unit presents in a large class of natural products isolated from plants, microorganisms and fungi (for selected reviews and book chapters, see: [ 1 – 8 ]). Representative natural product of this family is physostigmine (Fig. 1 , 1 ) which was isolated from the seeds of the calabar bean plant and is currently used to treat myasthenia gravis, glaucoma, Alzheimers disease, delayed gastric emptying and orthostatic hypotension [ 5 , 7 ]. There are a number of alkaloids containing more than one HPI unit and some of them contain a unique vicinal C3a– \({\text{C}}{{3{\text{a}}}}^{'}\) quaternary carbon center [ 1 , 4 ]. The stereocontrol synthesis of the congested all-carbon quaternary stereocenters in these alkaloids presents a formidable challenge [ 9 – 16 ]. In 1999, Overman and his team completed the first enantioselective synthesis of dimeric alkaloid (+)-calycanthine (Fig. 1 , 4 ) and (−)-chimonanthine (Fig. 1 , 2 ) [ 17 ]. Utilization of the same strategy, they also successfully synthesized a number of other dimeric and oligomeric HPI alkaloids [ 17 – 27 ]. In 2007, Mavassaghi reported a reductive radical dimerization strategy for the syntheses of dimeric HPI alkaloids (Fig. 1 ) [ 28 , 29 ]. Based on this reductive dimerization reaction, a number of important works have been published towards the syntheses of dimeric HPI alkaloids (for selected syntheses of dimeric HPI alkaloids employed Movassaghi’s reductive dimerization, see: [ 30 – 37 ]). Prompted by the success of reductive dimerization strategies, studies on the oxidative dimerization of tryptamine and tryptophan derivatives have been revived and syntheses of natural HPI alkaloids, especially chimonanthine, folicanthine and ditryptophenaline, have been achieved by a number of research groups (oxidative dimerization of tryptamine and tryptophan derivatives as the key steps for the syntheses of dimeric HPI alkaloids before 2007: [ 38 – 58 ]).
Institution: Yunnan University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: diamond
Awards: G1230651352, 步骤经济型反应及其应用研究, G36066560
OpenAlex ID: W2294714850