Catalytic Diastereoselective Synthesis of Diquinanes from Acyclic Precursors

Abstract

Upon exposure of up to 10 mol % tributylphosphine, electron-deficient 1,7-enynes undergo [3 + 2] cycloaddition to afford bicyclo[3:3:0] ring systems. In all but one case, products were obtained in >95:5 de, as determined by 1H NMR. This methodology enables concise and diastereoselective access to diquinane ring systems, whereby three contiguous stereogenic centers are set in a single manipulation.

Nucleophilic Phosphine Organocatalysis

“…(68), Scheme 6.3]. [60] Included in an array of substrates examined are cyclopropyl enones, which are generally incompatible with transition metal catalysis but which react smoothly under nucleophilic organocatalysis. Krische has applied the intramolecular [3 þ 2] reaction to the total synthesis of hirsutene [Eq.…”

Asymmetric total synthesis of (−)-lingzhiol via a Rh-catalysed [3+2] cycloaddition

“…It was envisaged that the use of an a,b-unsaturated aldehyde linked to an allenyl rhodium moiety could be used for an intramolecular [3 þ 2] cycloaddition reaction, which would allow for the formation of a cyclopentane ring 43,44 . Herein, we report the development of a new [3 þ 2] cycloaddition reaction between an enal and an alleno rhodium species, which was generated in situ by the Rh(I)-mediated retro-propargylation of homo-propargyl alcohol 45 , to give [3.3.0] and [4.3.0] bicyclic ring systems bearing two quaternary carbon centres at the bridgehead positions (Fig.…”

Phosphine‐Catalyzed Intramolecular Formal [3+2] Cycloaddition for Highly Diastereoselective Synthesis of Bicyclo[n.3.0] Compounds

“…[3] Recently, several ylide cyclizations that go beyond the formation of three-membered rings have also been developed. [4][5][6][7] Lu and co-workers demonstrated in a number of elegant studies [4] that phosphines are good catalysts for the construction of cyclopentenes. Krische and co-workers developed the first intramolecular variant of the cycloaddition.…”