Mercuric Triflate-Catalyzed Reaction of Propargyl Acetates with Water Leading Vinyl Ketones

Abstract

[reaction: see text]. Reaction of propargyl acetate with water catalyzed by Hg(OTf)2 afforded vinyl ketone as the major product along with a dimeric vinyl mercuric product and normal hydration products in small amounts. The reaction is an alternative to the Meyer-Schuster and Rupe rearrangement applicable to primary alcohols, although the mechanism is entirely different.

Unified Total Synthesis of (−)‐Enigmazole A and (−)‐15‐O‐Methylenigmazole A

“…Zhang conditions ([(Ph 3 P)AuNTf 2 ] 2 ⋅ toluene, moist 2‐butanone or CH 3 CN, RT) were completely ineffective and resulted in almost quantitative recovery of 26 a (entries 1 and 2). Nishizawa conditions (Hg(OTf) 2 , H 2 O, CH 3 CN, RT) [34] only caused partial hydration of the alkyne moiety (entry 3). The dinuclear Au complex 28 , which has been used for a [3,3]‐sigmatropic rearrangement of a propargylic acetate to an allenyl acetate in the Fürstner synthesis of (−)‐enigmazole A, [8] was also ineffective in this case (entry 4).…”

A new catalyst for organic synthesis: mercuric triflate

“…of H 2 O in CH 3 CN at room temperature selectively produces the enone 39 (Scheme 6). 23 Acid-catalyzed rearrangement of propargyl alcohols (not hydration) to give a,bunsaturated ketones is known as the Meyer-Schuster reaction. 24 This reaction is usually carried out under extreme conditions and it is applicable only to tert-alcohols.…”

A Simple and Versatile Re‐Catalyzed Meyer–Schuster Rearrangement of Propargylic Alcohols to α,β‐Unsaturated Carbonyl Compounds

“…More recent procedures are based on catalytic organometallic species. Thus, gold(I)6 or mercury(II)7 species catalyze the ready rearrangement of esters of propargylic alcohols to allenic esters and ultimately to the corresponding α,β‐unsatured carbonyl compounds; however, the atom and step economy of the overall transformations are obviously only moderate. Alternatively, Ru complexes promote the direct M.S.…”