Efficiency of Acid‐ and Mercury‐Catalyzed Cyclization Reactions in the Synthesis of Tetrahydrofurans from Allylsilyl Alcohols

Abstract

The scope of the acid‐catalyzed and mercury‐catalyzed cyclization reactions of allylsilyl alcohols is described. This methodology has been found to be an efficient approach to the synthesis of highly substituted tetrahydrofurans. The stereoselectivity of the cyclization is dependent both on the substitution of the starting alcohol and on the catalyst. A plausible mechanism has been proposed that is consistent with the results.

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

“…It had been cited in many publications that the stereoselectivity of products formed due to Hg(II)-salt-mediated cyclization reactions of alkene-alcohol derivatives depends on several factors: the nature of the Hg(II) salts [ 46 ], the starting materials [ 47 ], and the effect of H 2 O (protic solvent) in the reaction media [ 48 ].…”

“…Pulido et al had developed a conversion of allylsilyl alcohols 19 to diastereomeric mixtures of tetrahydrofuran derivatives 20A and 20B ( Scheme 9 ) [ 47 ]. It was reported that more substituted alkyl groups present in allylsilyl alcohol 20b direct the selective formation of diastereomeric products.…”

“…It was reported that more substituted alkyl groups present in allylsilyl alcohol 20b direct the selective formation of diastereomeric products. They also observed that changes in Hg(II) salts result in different ratios of the cis - and trans -isomer in the cyclized products [ 47 ]. The differences in cis and trans ratios were primarily due to the basicity of anions associated with Hg(II) salts [ 46 ].…”

Efficient access to polysubstituted tetrahydrofurans by electrophilic cyclization of vinylsilyl alcohols

“…12 We now present ours results on the cyclization of vinylsilyl alcohols, bearing the phenyldimethylsilyl group, to give di-, triand tetrasubstituted tetrahydrofurans in a stereoselective manner. 12 We now present ours results on the cyclization of vinylsilyl alcohols, bearing the phenyldimethylsilyl group, to give di-, triand tetrasubstituted tetrahydrofurans in a stereoselective manner.…”

Synthesis of Polysubstituted Tetrahydropyrans by Stereoselective Hydroalkoxylation of Silyl Alkenols: En Route to Tetrahydropyranyl Marine Analogues

“…For many years our research group has been devoted to exploring new synthetic approaches to the synthesis of carbo- [ 15 , 16 , 17 ] and heterocycles [ 18 , 19 ] using the chemistry of organosilanes. Lately, Hosomi [ 20 , 21 ] and our group [ 22 , 23 ] have reported an efficient synthesis of tetrahydrofurans by intramolecular hydroalkoxylation reaction of vinyl or allylsilanes. In this paper, we report the extension of this work to the stereoselective synthesis of polysubstituted tetrahydropyrans by the acid-mediated cyclization of activated vinylsilyl alcohols.…”