Two new approaches to the synthesis of sulfonyl‐functionalized allenecarboxylates and phosphorylated allenes are described. 2‐Sulfonyl‐alka‐2,3‐dienoates were readily prepared in an one‐pot reaction by [2,3]‐sigmatropic rearrangement of sulfinato‐substituted 2‐alkynoates, in situ generated from ethyl propynoate and subsequent treatment with lithium diisopropyl (LDA), ketone, trimethylchlorosilane (TMSCl), and the corresponding sulfinyl chlorides. Preparation of 1‐sulfonyl‐alka‐1,2‐dienephosphonates and ‐1,2‐dienyl phosphine oxides consists of the reaction of the lithio compounds, in situ generated from phosphorylated allenes and LDA, with the corresponding sulfonyl chlorides.

Reaction of the lithio compounds A, generated in situ from the corresponding allene-phosphonates 1 and -phosphine oxide 2 and lithium diisopropylamide, with different electrophilic reagents leads to formation of the l-benzyl-, l-allyl-, l-propargyl-, l-phenylthio-, l-phenylseleno-, l-methylsulfinyl-, l-trichloromethylsulfinyl- and l-(trimethylsilyloxy)sulfonyl-1,2-alkadiene-phosphonates and -phosphine oxides 3–13.

This paper discusses a reaction of phosphorylated α-hydroxyallenes with protected or unprotected hydroxy groups involving 5-endo-trig cyclizations. Various electrophilic reagents such as sulfuryl chloride, bromine, benzenesulfenyl and benzeneselenenyl chlorides have been applied. The paper describes the reaction of 1-hydroxyalkyl-1,2-dienephosphonates with electrophiles that produces 2-methoxy-2-oxo-2,5-dihydro-1,2-oxaphospholes due to the participation of the phosphonate neighbouring group in the cyclization. On the other hand, (1E)-alk-1-en-1-yl phosphine oxides were prepared as mixtures with 2,5-dihydro-1,2-oxaphosphol-2-ium halides in a ratio of about 1:2 by chemo-, regio, and stereoselective electrophilic addition to the C²-C³-double bond in the allene moiety and subsequent concurrent attack of the external (halide anion) and internal (phosphine oxide group) nucleophiles. The paper proposes a possible mechanism that involves cyclization and additional reactions of the phosphorylated α-hydroxyallenes.

The Diels‐Alder reaction of 1‐ and 3‐vinylallenyl sulfoxides and sulfones with dimethyl but‐2‐ynedioate proceeds with tandem cyclization, rearrangement, and aromatization leading to the formation of 4‐sulfinyl(sulfonyl)‐ or 3‐sulfinyl(sulfonyl)methyl‐substituted phthalates in good yields. #Dedicated to Professor Dr. Toru Minami from Kyushu Institute of Technology, Kitakyushu, Japan on the occasion of his 65th birthday.