Musina EI, Naumov RN, Kanunnikov KB, Dobrynin AB, Gómez-Ruiz S, Lönnecke P, Hey-Hawkins E, Karasik AA, Sinyashin OG. Chiral [16]-ane P
4N
2 macrocycles: stereoselective synthesis and unexpected intermolecular exchange of endocyclic fragments.
Dalton Trans 2018;
47:16977-16984. [PMID:
30451253 DOI:
10.1039/c8dt03214a]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chiral 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes were stereoselectively synthesized as pure RPSPSPRP isomers via a one-pot Mannich-type condensation reaction of 1,3-bis(arylphosphino)propane, formaldehyde and optically active, as well as racemic, primary amines. An unprecedented intermolecular exchange of endocyclic amino fragments of 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes was observed. The lability of the P-CH2-N fragment in macrocyclic aminomethylphosphines is the reason of the stereoisomerization, formation of products with medium-sized cycles as well as the exchange of endocyclic amino fragments. The mechanism of these transformations involving the formation of a methylenephosphonium intermediate and further intra- and intermolecular nucleophilic substitution is discussed.
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