An eleven-step. high-yielding (46%) synthesis of lu-hydroxyvitamin D-5 (2) Starting from vitamin D-2 (4) is described, in which a Julia olefination sequence is used for the construction of the (24R)-ethyl-substituted side chain.
An eleven-step. high-yielding (46%) synthesis of lu-hydroxyvitamin D-5 (2) Starting from vitamin D-2 (4) is described, in which a Julia olefination sequence is used for the construction of the (24R)-ethyl-substituted side chain.
An efficient method for the preparation of a C/D-ringsynthon for 20-epi-22-oxavitamin D3 analogues is developed based on Me3SiOSO2CF3 catalysed reductive etherification of a ketone with an alkoxytrimethylsilane in the presence of triethylsilane.