Functionalized Enantiomerically Pure [1.1.1]-, [2.1.1]-, [2.2.1]-, and [2.2.2]Triblattanes

摘要: The methylene (2, 7, 10) and spirocyclopropane derivatives (8, 11, 12) are made accessible from rac-trishomocubane(mono-, di-, tri-)ones optically pure unsaturated benzoannulated [2.1.1]- (19, 48), [2.2.1]- (30, 53), D3-symmetrical [2.2.2]triblattanes (3, 4) the enantiomers of these ketones by expeditious (one pot) ring enlargement olefination procedures. In case central [2.2.2]trienes (+)-3/(—)-3, novel members (CH)14 family, optical resolution is advantageously postponed to stage intermediate [2.2.2]triones (35, 41) effected via their (R,R)-2,3-butanediol acetals. α-diketone series only [2.1.1]dione (70) sufficiently stable allow isolation; tetrone 73 hexone 5 indirectly identified as quinoxalines 74 76, respectively. Tribenzo[2.2.2]triblattane (—)-4 established M-helical enantiomer X-ray crystallography. Generally thermal stabilization pathway triblattanes a [4 + 2] cycloreversion with primary products [e.g. (1α,2α,7α,10α)-tricyclo[8.4.0.02,7]tetradeca-3,5,9,11,13-pentaene (78) rac-3] being unstable under drastic reaction conditions required. stereochemical course perepoxidation rac-3 investigated.