Asymmetric total syntheses of hydroxylated piperidine alkaloids via the intramolecular reaction of γ-aminoallylstannane with aldehyde

Access to Chiral Diamine Derivatives through Stereoselective Cu-Catalyzed Reductive Coupling of Imines and Allenamides

“… 20 In contrast, amino-substituted allyl reagents 12 have been used in reactions employing carbonyl electrophiles to provide 1,2-aminoalcohols ( 16 ). 21 − 23 Recently, the Krische 22 group and our own lab 23 have developed reductive coupling 24 , 25 procedures for the catalytic generation of amino-substituted allyl reagents 12 and have studied their reactions with carbonyl electrophiles ( Scheme 2 C). These techniques represent orthogonal methodologies whereby the Krische 22a system employs a chiral Ir-catalyst and processes aldehyde electrophiles using an achiral allenamide ( 15 ), while our work utilizes a Cu-catalyst and a chiral allenamide ( 15a ) for reactions using ketone electrophiles.…”

“…Surprisingly, only a single example of such a strategy for the preparation of 1,2-diamines has been reported, which employs a lithiated derivative of 12 (M = Li) with chiral tert -butane­sulfinimide derived aldimines affording products in moderate yields with mixtures of branched and linear allylation products . In contrast, amino-substituted allyl reagents 12 have been used in reactions employing carbonyl electrophiles to provide 1,2-aminoalcohols ( 16 ). − Recently, the Krische group and our own lab have developed reductive coupling , procedures for the catalytic generation of amino-substituted allyl reagents 12 and have studied their reactions with carbonyl electrophiles (Scheme C). These techniques represent orthogonal methodologies whereby the Krische system employs a chiral Ir-catalyst and processes aldehyde electrophiles using an achiral allenamide ( 15 ), while our work utilizes a Cu-catalyst and a chiral allenamide ( 15a ) for reactions using ketone electrophiles .…”

Synthesis of two piperidine alkaloids, (−)-deoxoprosopinine and (−)-deoxoprosophylline, from 6-hydroxylated dihydrosphingosine derivatives

“…Indeed, there have been at least 17 different syntheses reported of the enantiomers of deoxoprosopinine 1 and deoxoprosophylline 3. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] These syntheses start from the chiral building blocks of natural (amino acids, 3,7,8,12,16 malic acid, 6 vitamin C 10 and carbohydrates 5,15,18,19 ) or synthetic origins. 4,9,11,13,14,17 In continuation of our recent work on (+)-carpamic acid 5, we became interested in synthesizing 1 and 3 by cyclization of the derivatives of sphingosine 6.…”

Stereoselective Synthesis of Piperidines

“…By using a chiral aldehyde derived from L-glutamic acid Yamamoto was able to extend this methodology to the enantioselective preparation of (+)-desoxoprosopinine. 157 In a related approach Hoffmann diastereoselectively converted allylboronates to 4-hydroxy-3-vinylpiperidines. 158 The required aldehyde moiety was generated in situ from the dimethylacetal by treatment with LiBF 4 .…”