Alkenyl naphthyl triflates

Catalytic asymmetric intramolecular Mizoroki-Heck reactions have been employed to synthesize several polyaromatic polyketide natural products. In one such endeavour, the catalytic asymmetric cyclization of alkenyl naphthyl triflate 84 was a central step in total syntheses of halenaquinone (88) and halenaquinol (89) recorded in the Shibasaki group laboratory (Scheme 16.19) [52]. Naphthyl triflate 84, which arose from Suzuki coupling of triflate 81 with alkylborane 82, was cyclized using the conditions that had become nearly... 

Aldehydes are prepared by carbonylation in the presence of hydride sources. Formation of aldehydes can be understood by transmetallation of acylpalladium 56 with a hydride to give acylpalladium hydride 57, followed by reductive elimination. Metal hydrides and hydrogen are used for aldehyde synthesis. Hydrosilane is one of the hydrides. Reaction of /I-naphthyl triflate (58) with EtsSiH using DPPF as a ligand under mild conditions afforded the aldehyde 59 [28]. Carbonylation of the alkenyl triflate 60 in the presence of tin hydride and LiCl afforded the aldehyde 61 in 95 % yield [29]. 

The alkenyl triflate 8 was reacted with the 2,3-dihydropyirole 12 and the product 16 was formed exclusively in 95% yield and with a greater than 99% ee (Scheme 11.9). Sonesson et al. [17] reported the arylation of 2,5-dihydropyrrole 17 with naphthyl triflate 18 using (1 )-B1NAP (5) and Pd(OAc)2 to give the 3-naphthyl product 19 in 34% yield and 58% ee (Scheme 11.10). 

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