Tunicaminyl uracil

Reductive coupling of RCHO and allylic alcohols A synthesis of tunicaminyl-uracil (5) involves a novel coupling of an aldehyde with an allylic alcohol, effected with dichlorodimethylsilane. Thus treatment of the alcohol 1 and the aldehyde 2 with bcnzenesclcnol and (CH,)2SiCI2 (excess) in pyridine at 23° provides the product 3 in 92% yield as a mixture of cpimers (1 1). Radical cyclization of 3 in acetonitrile with BuiSnll and (C2Hi)B, followed by siloxanc hydrolysis provides the protected... 

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