Diastereoselective synthesis of syn-β-methyl homoallyl alcohols with crotylmolybdenum complexes

✍ Scribed by J.W. Faller; M.J. DiVerdi; J.A. John

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 266 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)79643-2

✦ Synopsis

Air stable (cyclopentadienyl)Mo(NO)(halide)[~3-(Z)-crotyl] complexes add to aldehydes with high diastereoselectivity to yield syn-p-methyl homoallyl alcohols in up to 98% de. New routes to these reactive metal-(Z)-crotyl reagents utilize 2-butyne and s-&s-butadiene organomolybdenum intermediates instead of (Z)-crotylpotassium. Highly stereoselective additions of organometallic allyls to aldehydes have provided an important route for stereocontrolled synthesis of acyclic systems.' Crotylboron and crotyltitanium reagents have been particularly effective and the control of diastereoselectivity is generally attributed to binding of the aldehyde to a Lewis acid site and formation of a chairlike transition state. HO HO We have shown that anti-homoallyl alcohols can be conveniently prepared via reactions of aldehydes with CpMo(NO)(CI)[~3-(E)-crotyl]2 and our methodology has been applied by others to stereoselective 1,3-diol syntheses.3