Tris(trimethylsilyl)silane: an unprecedented enhancement in the diastereoselectivity of radical cyclisations to give 2,4-disubstituted piperidines.
Cyclisation of bromides 4a-f mediated by tributyltin hydride affords predominantly the trans piperidines 5a-f with modest diastereomeric ratios, while cyclisation with tris(trimethylsilyl)silane affords the same products with diastereomeric ratios of up to 99 : 1.
Gandon
Lucile A
LA
School of Chemistry, University of Birmingham, Edgbaston, Birmingham, UK B15 2TT.
Russell
Alexander G
AG
Snaith
John S
JS
D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D015394:Molecular Structure; D010880:Piperidines / Q000737:chemistry*; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D005609:Free Radicals; D010880:Piperidines; D012821:Silanes; C510691:tris(trimethylsilyl)silane