Second-generation synthesis of azadirachtin: a concise preparation of the propargylic mesylate fragment.
A second bite of the apple: A new and highly efficient synthesis of the propargylic mesylate fragment of azadirachtin has been accomplished (see scheme; Bn = benzyl, Ms = methanesulfonyl, PMB = para-methoxybenzyl, TBDPS = tert-butyldiphenylsilyl). An enantioselective catalytic hetero Diels-Alder reaction sets up the stereocenter at C15, which then controls the installation of the remaining functionality in a total of only 17 steps.
Boyer
Alistair
A
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
Veitch
Gemma E
GE
Beckmann
Edith
E
Ley
Steven V
SV
D002384:Catalysis; D007783:Lactones / Q000737:chemistry; D036701:Limonins / Q000138:chemical synthesis* / Q000737:chemistry; D008698:Mesylates / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism
D007783:Lactones; D036701:Limonins; D008698:Mesylates; C010329:azadirachtin