Cytlak T, Skibińska M, Kaczmarek P, Kaźmierczak M, Rapp M, Kubicki M, Koroniak H. Functionalization of α-hydroxyphosphonates as a convenient route to
N-tosyl-α-aminophosphonates.
RSC Adv 2018;
8:11957-11974. [PMID:
35539392 PMCID:
PMC9079259 DOI:
10.1039/c8ra01656a]
[Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 03/14/2018] [Indexed: 11/21/2022] Open
Abstract
Direct conversion of the α-hydroxyl group by para-toluenesulfonamide to yield α-(N-tosyl)aminophosphonates is reported. α-Aminophosphonates 23a,b-37a,b were obtained from the corresponding α-hydroxyphosphonates 6a,b-21a,b in the presence of K2CO3, via the retro-Abramov reaction of the appropriate aldehydes, 1-5. The subsequent formation of imines with simultaneous addition of diethyl phosphite provided access to the α-sulfonamide phosphonates 23a,b-37a,b with better diastereoselectivity than in the case of the Pudovik reaction. The mechanism for this transformation is proposed herein. When Cbz N-protected aziridine 9a,b and phenylalanine analogue 12a,b were exploited, intramolecular substitution was observed, leading to the corresponding epoxide 38 as the sole product, or oxazolidin-2-one 39 as a minor product. Analogous substitution was not observed in the case of proline 18a,b and serine 21a,b derivatives.
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