Aza-Sakurai-Hosomi reaction

AZA-SAKURAI-HOSOMI REACTION ASSOCIATED WITH HYDROFORMYLATION... 

SCHEME 2 Azaheterocycle syntheses from the aza-Sakurai-Hosomi reaction. 

J. Org. Chem. 2(X)4, 69,4(X)5—4(X)6. Iodine as a very powerful catalyst for three-component synthesis of protected homoal-lylic amines, (c) J.-R. Ella-Menye, W. Dobbs, M. BUlet, P. Klotz, A. Mann, Tetrahedron Lett. 2005, 46, 1897-19(X). Unexpected 1,2 syn diastereoselectivity in the three-component aza Sakurai-Hosomi reaction, (d) M. Sugiura, K. Hirano, S. Kobayashi, J. Am. Chem. Soc. 2004, 126, 7182-7183. a-Aminoallylation of aldehydes with ammonia stereoselective synthesis of homoallylic primary amines, (e) M. BiUet, P Klotz, A. Mann, Tetrahedron Lett. 2(X)1,42, 631-634. Syn diastereoselectivity in the synthesis of homoallylamine using crotylsilane in the three-component reaction, (f) L. Niimi,... 

To continue this work, it seemed interesting to us to try to apply this methodology to develop a slightly more complicated skeleton, that of a quinolizidine. For this, the thesis work of Etienne Airiau included designing an effective strategy involving few steps and allowing the production of a substituted bicyclic structure. Hence, we applied the combination of the aza-Sakurai-Hosomi/CHC process followed either by a cross-metathesis reaction or by a new hydroformylation reaction. ... 

In this chapter, only the most recent multicomponent versions of the Hosomi-Sakurai reaction will be covered [68b], in particular those that allowed the synthesis of homoallylic ethers through the combination of an aldehyde (or ketone) with a silyl ether or the corresponding alcohol and an allylsilane (Scheme 12.13, Eq. 1). And also, the synthesis of homoallylic amines where the allylsilane reacts with an imine in situ formed from the carbonyl compound and an amine is known as aza-Sakurai reaetion (Scheme 12.13, Eq. 2). 

SCHEME 12.13 Multicomponent (aza-)Hosomi-Sakurai reactions synthesis of homoallylic ethers (Eq. 1) and synthesis of homoaUylic amines (Eq. 2). 

Another short synthesis of ( )-9a-ep(-quinolizidine 195C (rat-2318), by Mann and coworkers, is worth mentioning in view of its use of a Hnear hydroformylation of a homoallylamine (cyclohydrocarbonylation) to constmct the piperidine ring (Scheme 296). ° A three-component aza-Hosomi—Sakurai reaction between allyltrimethylsilane, butanal, and O-benzylurethane catalyzed by boron trifluoride was used to form the protected homoallylamine ( )-2319. The cyclohydrocarbonylation was then performed with a biphephos/rhodium(I) catalytic system in methanol, yielding the piperidine-containing hemiaminal 2320 in 84% yield. This... 

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