A Facile Diastereoselective Synthesis of Functionalized 1,2,3-Trisubstituted Benzocyclopentenes through the Cycloaddition of Bis(phenylsulfonyl)iodonium Ylides to Cyclic Alkenes

Abstract

The thermal cycloaddition of beta-disulfonyl iodonium ylides to cyclic alkenes affords exclusively 1,2,3-trisubstituted cis(1,2)/cis(2,3)-configured benzocyclopentenes by an electrophilic attack of the ylide on the olefinic double bond. This unsual transformation provides a convenient and direct method for the diastereoselective synthesis of functionalized bicyclo[3.3.0]octanes (characteristic structural units contained in polyquinane natural products), when cyclopentenes are used as cycloalkene partner.

The Reaction of PhenyliodoniumBis(phenylsulfonyl)methylide with Alkyl Iodides

“…The exo-conformation of the C-2, C-3 substituents results from the absence (COSY) of a coupling between H-2 and H-3 with the adjacent bridgehead protons. 18 In accord with our previous proposal [11][12][13] and the current results, we offer the mechanism in Scheme 4 to rationalize the formation of the adduct 7. The reaction is presumably initiated by the fast reaction of iodonium ylide 1 with methyl iodide to afford the unstable alkyliodonium ylide 5a.…”

“…Iodonium ylide 1 affords with acyclic 1,2-disubstituted alkenes (cis or trans), the trans,trans-1,2,3-trisubstituted indanes 11 (Scheme 1), whereas, with cyclic alkenes the cis,cis-1,2,3-trisubstituted indanes were isolated instead. 12 But this cycloaddition depends heavily on the substitution pattern of the alkene. Introduction of another substituent into the alkene, such as in triphenylethylene and tetraphenylethylene, results in an alkenyl or aryl C-H insertion reaction.…”

Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents

“…For instance, intramolecular trapping of the enamine generated upon catalytic addition of bisA C H T U N G T R E N N U N G (sulfone) 4 to enal 22, and subsequent desulfonation of the intermediate 23, led to trisubstituted indane derivative 24 with the ester group transesterified and featuring an unusual cis,trans substitution pattern (Scheme 5). [17,18] This catalytic tandem Michael-Michael process involves a cyclopentane anulation with the generation of two new C-C bonds and three contiguous stereocenters in one pot, a reaction in which a survey of pronucleophiles are anticipated to be involved with equal efficiency. [19,20] Interestingly, by just avoiding benzoic acid as the cocatalyst, the simple addition adduct 25 was isolated in 78 % yield.…”

Iodonium ylides in organic synthesis

“…[14][15][16] The product composition in the rhodium(II)-catalyzed reactions of iodonium ylides was found to be identical to that of the corresponding diazo compounds, which confirms that mechanisms of both processes are similar and involve metallocarbenes as key intermediates. Rh(II)-or Cu(II)-catalyzed generation/rearrangement of onium ylides of allyl and benzyl ethers via iodonium ylides; 82 and Rh(II)-or Cu(II)-catalyzed stereoselective cycloaddition of disulfonyl iodonium ylides with alkenes leading to 1,2,3-trisubstituted benzocyclopentenes 83 or functionalized indanes. [84][85][86] Moriarty and co-workers have investigated the intramolecular cyclopropanation of iodonium ylides to the tricyclic ketones in the presence of copper(I) chloride and also in the absence of conventional metal calalysts.…”