Takehiko Yoshimitsu

An approach to the synthesis of CP-263,114: complementary routes to the bicyclic ring system via two kinds of fragmentation reaction

Abstract Two complementary methods for the construction of the ring system of CP-263,114 ( 1 ), one relying on the Grob fragmentation reaction and the other on a sequential photolytic alkoxy radical fragmentation-reduction, are described.

A new synthetic route for construction of the core of Zaragozic acids

Abstract A new synthetic route for construction of the core moiety of zaragozic acids from 2,5-furandimethanol ( 2 ) is described. This synthesis involves highly stereocontrolled transformation of 2 into 7-oxabicyclo[2.2.1]heptane derivative 13 , and the Grob fragmentation-reduction-iodo acetalization reaction (one-pot process) of 13 as a key step to give 16 .

Synthesis of the CD ring system of paclitaxel by atom-transfer radical annulation reaction

Abstract Atom-transfer radical annulation of diene derived from d -glucose under Kharasch conditions provided access to the fully functionalized CD ring system of paclitaxel.

New route to the synthesis of the illudane skeleton by Michael-Michael- elimination reaction

Abstract A new route to the synthesis of an optically active illudane skeleton from ( R )-(−)-pantolactone ( 4 ) is established. The tricyclic ring system was constructed by Michael–Michael-elimination reaction of the enolate of (3 S ,5 R )-3-( tert -butyldimethylsilyloxy)-5-methoxymethyloxy-1-propionylcyclopentene ( 10 ) with ethyl cyclopropylidenacetate ( 3 ).

New method for the synthesis of α-substituted tetrahydrofuran-2-methanols through diastereoselective addition of THF to aldehydes mediated by Et3B in the presence of air

The tetrahydrofuranyl radical, generated from THF with Et3B in the presence of air, was found to react with aldehydes threo-selectively to afford α-substituted tetrahydrofuran-2-methanols, the common structural motifs of biologically active acetogenin polyketides, in moderate yields.