An environmentally benign synthesis of cis-2,6-disubstituted tetrahydropyrans via indium-mediated tandem allylation/Prins cyclization reaction.
In the presence of indium metal, 3-iodo-2-[(trimethylsilyl)methyl]propene (1) reacts with sequentially added aldehydes to provide cis-2,6-disubstituted tetrahydropyrans in good yields. Evidence suggests that InI, formed upon aldehyde (R1CHO) allylation in aqueous media, acts as a promoter for the silyl-Prins reaction with the second equivalent of added aldehyde (R2CHO). The preparation of cyclohexenyl-fused pyrans via this one-pot, three-component coupling process is presented, as is a short formal synthesis of (+/-)-centrolobine.
Pham
Minh
M
Department of Chemistry and Biochemistry, California State University-Northridge, Northridge, California 91330, USA.
Allatabakhsh
Amir
A
Minehan
Thomas G
TG
D000478:Alkylation; D000498:Allyl Compounds / Q000138:chemical synthesis*; D003500:Cyclization; D007204:Indium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014297:Trimethylsilyl Compounds / Q000737:chemistry
D000498:Allyl Compounds; D011714:Pyrans; D014297:Trimethylsilyl Compounds; D007204:Indium