Synthesis and Absolute Configuration of Optically Active D3-Tritwistane, the Gyrochiral Prototype of "Twist" Diamond

Article abstract of DOI:10.1021/jo00324a018

A modification of Barborak's trishomocubane synthesis, when applied to the higher homologue, afforded 8,12-diacetoxy-C₂-bismethanotwistane (21) which was converted into (+/-)-4-C₂-methanoditwistanone (29) by a sequence of conversions involving diazomethane ring expansion of the intermediate keto acetates 24 and 25.Incubation of the resulting C₂-ketone 29 with Rhodotorula rubra yielded a mixture of the (-)-C₂-ketone 29 and the (+)-C₂-alcohol 28 with respective 15percent and 33percent optical purities.Our proposed microbial C₂-ketone rule coupled with CD analysis assigned the 3S,5S configuration to the (-)-C₂-ketone 29 whose Wolff-Kishner reduction gave (-)-C₂-methanoditwistane (9).Demjanov rearrangement of the amine 31 prepared from the (-)-C₂-ketone 29 followed by removal of the functional group provided (-)-D₃-tritwistane (10) (_D,abs -1067 deg), the prototype of "twist" diamond, which was found to be converted into diamantane (congressane, 42) by aluminium bromide treatment.