Acyclic Allyl Alcohol Derivatives

One of the classical ways to perform diastereoselective 1,3-dipolar cycloaddition is by the addition of a 1,3-dipole to an allyl alcohol derivative (65, 107-120). Very recently, a short review article was devoted to this area (13). Among the most commonly applied acyclic allyl alcohol derivatives are alkenes 73-75 (Scheme 12.25). These alkenes have been used in reactions with nitrones. 

Cyclizations of chloral hemiacetal derivatives of cyclic allyl alcohols were regio- and stereo-selective (Table 6, entry 1), but a mixture of regioisomers was obtained from analogous derivatives of acyclic allyl alcohols with a nonterminal double bond.93 Hemiacetal derivatives of allyl alcohols with a terminal vinyl group have been cyclized with mercury(II) acetate to give acetal derivatives of threo 1,2-diols with moderate selectivities (equation 54 and Table 15, entries 1 and 2).147 Moderate to excellent stereoselectivity has been observed in the iodocyclizations of carbonate derivatives of allyl alcohols (entries 3-5).94a The currently available results do not provide a rationale for the variation in observed stereoselectivity. 

Table 15 O-Cyclizations of Derivatives of Acyclic Allylic Alcohols (Equation 54)...

Hydroboration of alkenes1 (15, 91). The Rh(I)-catalyzed hydroboration provides a highly diastereoselective reaction in a synthesis of a poly ether antibiotic. Thus the derivative (1) of an acyclic allylic alcohol is converted to the primary alcohol 2 by hydroboration with catecholborane (CB) catalyzed by ClRh[P(C6H5)3]3 with 94 6 selectivity. Note that hydroboration of 1 with disiamylborane (12, 484) proceeds with the opposite selectivity at Cio (8 92). 

Stereoselective cyclopropanation of acyclic allylic alcohols glucose-derived chiral auxiliary24 1... 

A CM reaction of the allylic alcohol derivative 130 and the enone 131 provided the acyclic precursor 132 for the synthesis of (+)-carpamic acid 133 <04TL1167>. 

Chamberlin AR, Dezube M, Dussault P, McMills MC (1983) Iodocyclization of allylic alcohol derivatives containing internal nucleophiles. Control of stereoselectivity by substituents in the acyclic precursors. J Am Chem Soc 105 5819-5825... 

An allylic sulfenate, like 199, is known to be in equilibrium with allylic sulfoxide, like 196, although its concentration is usually low . Various allylic sulfoxides can be prepared by treatment of allylic alcohols with arenesulfenyl chlorides . Evans and coworkers prepared various allylic alcohols by treating the corresponding allylic sulfoxides with trimethyl phosphite. For example, the carbanion from a cycloalkenyl sulfoxide 201 was readily alkylated at the a-position by treatment with alkyl halide. The resulting alkylated derivative 202 was then treated with trimethyl phosphite and 3-substituted cycloalkenol was obtained. Alkylation of acyclic allylic sulfoxide 204 gave... 

The 1,2-addition of allyl iodide to cyclic and acyclic a,/ -unsaturated carbonyl compounds has been achieved by using indium and indium trichloride. The reactivities of a,/3-unsaturated carbonyl compounds depend upon their structure. The reaction of ketones smoothly undergoes in THF or DMF. In the case of cyclic ketones, however, the solvent plays a crucial role, where much improved yields have been obtained in DMF than in THF (Equation (49)).236 Indium-mediated 1,2-allylation of /3-bromoacrolein produces homoallylic alcohol derivatives (Equation (50)), which can be transformed to cyclopentanones by a Pd-catalyzed cyclization.237,238... 

The mercury-initiated cyclization of acylaminomethyl ether derivatives, obtained from acyclic allylic and homoallylic alcohols, proceeded in good yield to give either oxazolidines or 1,3-ox-azinanes. These heterocycles are readily hydrolyzed, hence, this method can be used to prepare amino alcohols starting from allylic and homoallylic alcohols. 

Located at an "ofif-template" site, we expected the Cl 4 center to be more difficxilt to establish and verify. We were going to have to rely on precedents of acyclic stereoselection, and based on Kishi s empirical observations (ref. 30), hydroxylation of olefin 32b should have given the R epimer 33, preferentially. On the other hand. Cram chelate addition (ref. 31), as elaborated by Still (ref. 32), to the a-benzyloxy ketone 32a, should give the allyl alcohol 34 from which the S-epimer 35 could be derived. Indeed, both processes were entirely stereoselective, and we were able to prepare the two possible products, each as a single isomer. 

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