New Efficient Construction of the ABC Core of the Taxoids via a Sequence of Consecutive Cobalt(I)-Mediated [2 + 2 + 2] and [4 + 2] Cyclizations
摘要:
[GRAPHICS]A new and efficient sequence of two consecutive cyclizations, a cobalt(I)-mediated [2 + 2 + 2] cyclotrimerization and a Diels-Alder reaction, is proposed to allow the formation of the ABC core of the taxoids in 65% overall yield, starting from an acyclic polyunsaturated precursor.
New Efficient Construction of the ABC Core of the Taxoids via a Sequence of Consecutive Cobalt(I)-Mediated [2 + 2 + 2] and [4 + 2] Cyclizations
摘要:
[GRAPHICS]A new and efficient sequence of two consecutive cyclizations, a cobalt(I)-mediated [2 + 2 + 2] cyclotrimerization and a Diels-Alder reaction, is proposed to allow the formation of the ABC core of the taxoids in 65% overall yield, starting from an acyclic polyunsaturated precursor.
The construction of the AB taxane ring system through a [4+2] reaction and Co(I)-[2+2] cyclization is presented. For the first time, CpCo(CO)2 catalyzes the ring closure of strained polyunsaturated triynic compound into eight-memberedring.