Rh(I)-catalyzed bimolecular cyclization between two different 1,5-bisallenes: a combinatorial one-step approach to heterosteroids and mechanistic implications.
In this paper, a bimolecular-cyclization reaction between two different bis(allene)s with at least one heteroatom as the tether under the catalysis of trans-[RhCl(CO)(PPh3)2] is described. This protocol provides an efficient entry to different heterocyclic 18,19-norsteroid-like scaffolds. The tricyclic product was formed highly selectively from the cyclization reaction of bis(2,3-butadienyl)sulfide with dimethyl 2-bis(2',3'-butadienyl)malonate, which sheds light on the mechanism involving the metalla-[4.3.0]-bicyclic intermediate formed by the cyclometallation of the terminal and the internal C=C bonds of each of the two allene moieties in 2-bis(2',3'-butadienyl)malonate.
Ma
Shengming
S
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China. masm@mail.sioc.ac.cn
Lu
Lianghua
L
D000466:Alkadienes / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry*; D013260:Steroids, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry
D000466:Alkadienes; D013260:Steroids, Heterocyclic; C025947:propadiene; D012238:Rhodium