Organometallic enantiomeric scaffolding. Sequential semipinacol/1,5-"Michael-like" reactions as a strategic approach to bridgehead-quaternary center aza[3.3.1]bicyclics: application to the total synthesis of (-)-adaline.
A nontraditional approach to the enantiocontrolled construction of quaternary center-bearing heteroatom-bridged bicyclo[3.3.1]nonanes (homotropanes) is reported that is based on organometallic enantiomeric scaffolding. This strategy takes advantage of the unique reactivity profiles of TpMo(CO)(2)(5-oxo-eta(3)-pyranyl) and TpMo(CO)(2)(5-oxo-eta(3)-pyridinyl) scaffolds, and features a molybdenum-mediated semipinacol/1,5-"Michael-like" reaction sequence to establish the quaternary center and synthesize the bridged bicyclic structure. An asymmetric total synthesis of (-)-adaline highlights this methodology.
Coombs
Thomas C
TC
Sanford S. Atwood Chemistry Center, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
Zhang
Yongqiang
Y
Garnier-Amblard
Ethel C
EC
Liebeskind
Lanny S
LS
D001372:Aza Compounds / Q000737:chemistry*; D001643:Bridged Bicyclo Compounds / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010880:Piperidines / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D013237:Stereoisomerism
D001372:Aza Compounds; D001643:Bridged Bicyclo Compounds; D001952:Bridged-Ring Compounds; D010880:Piperidines; D011725:Pyridines; C475960:adaline; C023666:pyridine