Naoyuki Kishi

Asymmetric allylsilane-mediated carbocyclization: A highly enantiospecific synthesis of (1S, 2S)-(+)-2-methyl-3-cyclopenten-1-ol

An enantiospecific synthesis of the title compound is described which involves the TiCl4-promoted cyclization of the chiral allylic silane having formyl group, which was obtained via the Claisen rearrangement of (R, E)-1-trimethylsilyl-1-buten-3-ol.

Intramolecular acylation of vinylic silanes. A novel, general approach for the synthesis of four- to six-membered carbocyclic systems and its regiochemical features

Abstract Intramolecular acylations of m-trimethylsilyl-m-alkenoyl chlorides (m = 4 and 5) are described which afford the expected α-alkylidenecycloalkanone and/or the unexpected cycloalkenone, depending upon the substrate structure.

New sigmatropic sequences based on the [2,3]-wittig rearrangement of the bis-allylic ether system : A general approach to regiocontrolled c—c bond formation of allylic moieties leading to unsaturated carbonyl compounds

Abstract Four new sigmatropic sequences triggered by the regiocontrolled [2,3]-Wittig rearrangement of unsymmetrical bis-allylic ethers (1) to the l,5-dien-3-ols (2) arc described, which provide unique, regiocontrolled methods for the synthesis of a wide variety of unsaturated carbonyl compounds possessing interesting molecular frameworks. The newly developed sequences include the [2,3]-Wittig-Claisen, the tandem [2,3]-Wittig-oxy-Cope, the tandem oxy-Cope-Claisen, and the tandem oxy-Cope-Cope sequences.

[2,3]Wittig rearrangement-peterson olefination sequence: a stereocontrolled entry to terminal conjugated trienes

Abstract A new and highly stereocontrolled entry to terminal conjugated trienes is described which relies upon the diastereoselective [2,3]Wittig rearrangement of > (silyl)allylic propargyl ethers followed by Peterson olefination. The synthetic utility of this method is demonstrated by the stereocontrolled synthesis of sarohornene B and C (marine natural products).

Olefinic stereoselection in the [2,3]-Wittig rearrangement of α,β-disubstituted allylic ethers forming trisubstituted olefins

Abstract The E Z - selectivities in the [2,3]-Wittig rearrangements of secondary β-(methyl or silyl)allylic ethers are shown to depend critically on the nature of groups on the carbanion terminus, thereby permitting elucidation of the structural requirements for attaining high Z-selectivity.

Vinylsilane-terminated cycloacylation: A general synthetic approach to four- to six-membered cyclic ketones and its regiochemical features

Abstract Intramolecular acylations of m-trimethylsilyl-m-alkenoyl chlorides (m=4 and 5) are described which afford the expected α-alkylidenecycloalkanone and/or the unexpected cycloalkenone, depending markedly upon the substitution pattern on the vinylsilane moiety and/or the chain length (m).