Highly Stereocontrolled One-Step Synthesis ofanti-β-Amino Alcohols from Organoboronic Acids, Amines, and α-Hydroxy Aldehydes

Concise synthesis of (−)-steviamine and analogues and their glycosidase inhibitory activities

“…The configuration at the newly created, amino group bearing, stereogenic centre in 11a, that would become C-8a in the final target 1, was assumed to the desired one based on reports that the PBAMR normally provides 1,2-anti-amino alcohol products via a boronate intermediate, similar to A, as shown in Scheme 1. 7,8 This assumption was later confirmed to be correct in the eventual execution of the synthesis of 1. Treatment of 11a with 1.07 equivalents of methanesulfonyl chloride and 3.5 equivalents of triethylamine, 8(g) followed by warming of the O-mesylate intermediate to 40−45 o C for 4 h provided the fully substituted pyrrolidine 12a in 66% yield after separation of small amounts of O,N-dimesylated 11a and unreacted 11a by column chromatography.…”

“…The synthesis of (-)-steviamine 1 started with a Petasis boronic acid Mannich reaction (PBAMR) 7,8 between the known L-β-ribofuranose derivative 8 9 ((3S,4R,5S)-4-(benzyloxy)-5-(benzyloxymethyl)tetrahydrofuran-2,3-diol) and commercially available (R)-4-penten-2-amine.HCl 9a and E-styrylboronic acid 10 (Scheme 1). Stirring these three components in the presence of triethylamine (to generate the free amine of 9a) in ethanol at rt for 4 d, gave, after purification of the crude reaction mixture by column chromatography, the amino alcohol 11 in 77% yield, as a single diastereomer.…”

Synthesis, X-ray crystal structure and antimycobacterial activity of enantiomerically pure 1-ethyl-2,3-dicyano-5-(het)aryl-6-hetaryl-1,6-dihydropyrazines

“…[17][18][19][20][21][22][23][24][25][26] On the other hand, the Petasis reaction is one of the multicomponent condensation reactions, which provides a convenient method for the preparation of α-amino acids by reacting an amine 1 with a carbonyl compound 2 and a boronic acid 3. [27][28][29][30][31][32][33][34] The reaction proceeds via the formation of aminal intermediate 4 (Scheme 1). The reaction has also been applied to the synthesis of heterocyclic systems [35][36][37][38][39][40] and solid phase synthesis of peptides.…”

A Convenient Synthesis of Immunosuppressive Agent FTY720 Using the Petasis Reaction

“…9) On the other hand, Petasis reported a Mannich-type coupling reaction of vinyl-and arylboronic acids, amines and ahydroxyalkyl carbonyl compounds to afford aminoalcohols. [10][11][12] It was envisaged that this methodology would allow an efficient synthesis of FTY720 (1) via the synthetic elaboration of the 2-amino-1,3-propanediol 2 derived from the Petasis reaction of (E)-2-(4-octylphenyl)ethenylboronic acid (4), dihydroxyacetone (3) and benzylamine (Chart 1).…”