Ps. Aburel et al., Rhodium(II)-carbenoid C-H insertion reactions in the synthesis of alpha,beta '-dioxospirane systems, J CHEM S P1, (9), 2001, pp. 1024-1029
Spiro[4.4]nonane-, spiro[4.5]decane- and spiro[4.6]undecane-alpha,beta'-dio
nes have been prepared from 1-diazo-4-(2,2-ethylenedioxycycloalkan-1-yl)but
an-2-one intermediates by Rh-2(OAc)(4)- and Rh-2(TPA)(4)-catalyzed C-H inse
rtions. Competitive insertions also gave trans-bicyclic derivatives. The re
lative stereochemistry in bicyclic derivatives has been determined by singl
e crystal X-ray analyses.